U.S. patent number 6,639,555 [Application Number 09/486,332] was granted by the patent office on 2003-10-28 for antenna unit, communication system and digital television receiver.
This patent grant is currently assigned to Matsushita Electric Industrial Co., Ltd.. Invention is credited to Joji Kane, Noboru Nomura, Michio Sasaki, Satoshi Yamada, Akinori Yanase, Takasi Yosida.
United States Patent |
6,639,555 |
Kane , et al. |
October 28, 2003 |
**Please see images for:
( Certificate of Correction ) ** |
Antenna unit, communication system and digital television
receiver
Abstract
An antenna device comprising a conductive earth substrate, a
receiving element located in the proximity of said conductive earth
substrate and having a receiving terminal, and a transmitting
element located in the proximity of said receiving element and
having a transmitting terminal, characterized in that an end of
said receiving element and an end of said transmitting element are
connected to said conductive earth substrate for grounding through
a common portion and the frequency band of said receiving element
is different from that of said transmitting element.
Inventors: |
Kane; Joji (Nara,
JP), Yosida; Takasi (Ikoma, JP), Nomura;
Noboru (Kyoto, JP), Sasaki; Michio (Yokohama,
JP), Yanase; Akinori (Yokohama, JP),
Yamada; Satoshi (Yokohama, JP) |
Assignee: |
Matsushita Electric Industrial Co.,
Ltd. (Osaka, JP)
|
Family
ID: |
16215293 |
Appl.
No.: |
09/486,332 |
Filed: |
May 31, 2000 |
PCT
Filed: |
December 10, 1998 |
PCT No.: |
PCT/JP98/05577 |
PCT
Pub. No.: |
WO00/02287 |
PCT
Pub. Date: |
January 13, 2000 |
Foreign Application Priority Data
|
|
|
|
|
Jul 2, 1998 [JP] |
|
|
10-187967 |
|
Current U.S.
Class: |
343/700MS;
343/815; 725/70 |
Current CPC
Class: |
H01Q
9/0414 (20130101); H01Q 5/50 (20150115); H01Q
21/28 (20130101); H01Q 5/378 (20150115); H01Q
9/42 (20130101); H01Q 1/36 (20130101); H01Q
9/0421 (20130101); H01Q 5/371 (20150115); H01Q
5/40 (20150115); H01Q 3/26 (20130101); H01Q
23/00 (20130101); H01Q 5/321 (20150115); H01Q
9/14 (20130101); H01Q 1/32 (20130101); H01Q
21/30 (20130101) |
Current International
Class: |
H01Q
1/36 (20060101); H01Q 23/00 (20060101); H01Q
21/00 (20060101); H01Q 9/04 (20060101); H01Q
5/00 (20060101); H01Q 1/32 (20060101); H01Q
3/26 (20060101); H01Q 21/28 (20060101); H01Q
9/42 (20060101); H01Q 21/30 (20060101); H01Q
001/38 () |
Field of
Search: |
;343/7MS,713,702,815,860,861 ;725/70,52 ;348/563 ;455/3.02
;375/261,321 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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56-713 |
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56-31235 |
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64-38845 |
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7-336130 |
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9-181699 |
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Oct 1997 |
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10-107777 |
|
Apr 1998 |
|
JP |
|
Primary Examiner: Ho; Tan
Attorney, Agent or Firm: Smith, Gambrell & Russell,
LLP
Claims
What is claimed is:
1. An antenna device comprising: a conductive earth substrate; a
receiving element located in the proximity of said conductive earth
substrate and having a receiving terminal; and a transmitting
element located in the proximity of said receiving element and
having a transmitting terminal, characterized in that an end of
said receiving element and an end of said transmitting element are
connected to said conductive earth substrate for grounding through
a common portion and the frequency band of said receiving element
is different from that of said transmitting element.
2. The antenna device according to claim 1, characterized in that
said receiving element and/or said transmitting element consists of
a plurality of elements.
3. The antenna device according to claim 1, characterized in that
said receiving element and said transmitting element are formed
together on one side of a common circuit board.
4. The antenna device according to claim 3, characterized in that a
receiving amplifier is provided on said common circuit board
between said receiving element and said receiving terminal.
5. The antenna device according to claim 4, characterized in that
said receiving amplifier is provided on the opposite side of said
common circuit board to said receiving element and said receiving
amplifier is connected to said receiving element via a through-hole
provided in said common circuit board.
6. The antenna device according to claim 3, characterized in that a
transmitting amplifier is provided on said common circuit board
between said transmitting element and said transmitting
terminal.
7. The antenna device according to claim 6, characterized in that
said transmitting amplifier is provided on the opposite side of
said common circuit board to said transmitting element and said
transmitting amplifier is connected to said transmitting element
via a through-hole provided in said common circuit board.
8. The antenna device according to claim 3, characterized in that a
receiving amplifier and a transmitting amplifier are provided on
said common circuit board between said receiving element and said
receiving terminal and between said transmitting element and said
transmitting terminal, respectively.
9. The antenna device according to claim 3, characterized in that
said receiving terminal and said transmitting terminal are
implemented as a single common terminal by using a common
component.
10. A communication system comprising: an antenna device according
to claim 9; a communication device having a power supply section to
supply electric power to said receiving amplifier of said antenna
device and capable of both transmitting and receiving; and a
feeding line for connecting a common terminal of said antenna
device to a signal input/output section of said communication
device, characterized in that a direct-current blocking capacitor
is provided between a common component of said antenna element and
said common terminal and at the input/output terminal of said
communication device, respectively, and electric power is supplied
by said power supply section to a receiving amplifier of said
antenna device through said feeding line.
11. The communication system according to claim 10, characterized
in that said power supply section is controlled to turn on/off by
using a switch signal to change over to the transmission operation
in said communication device.
12. The antenna device according to claim 1, characterized in that
said receiving element and said transmitting element are formed
separately on opposite sides of a common circuit board.
13. The antenna device according to claim 1, characterized in that
said receiving element and/or said transmitting element and/or said
receiving terminal and/or said transmitting terminal is provided
with a trap circuit having a predetermined resonance frequency.
14. The antenna device according to claim 1, characterized in that
said receiving element and/or said transmitting element and/or said
receiving terminal and/or said transmitting terminal is provided
with a band-pass circuit having a resonance frequency substantially
equal to that of the antenna.
15. A communication system comprising: an antenna device according
to claim 1, a communication device having a receiving amplifier and
a transmitting amplifier; a receiving connection line for
connecting the receiving terminal of said antenna device to said
receiving amplifier of said communication device; and a
transmitting connection line for connecting the transmitting
terminal of said antenna device to said transmitting amplifier of
said communication device.
16. The antenna device according to claim 1, characterized in that
at said receiving terminal and/or said transmitting terminal, a
low-pass circuit is provided to pass signals of lower frequencies
including a tuning frequency of the antenna and to block signals of
frequencies higher than the tuning frequency of the antenna.
17. The antenna device according to claim 1, characterized in that
at said receiving terminal and/or said transmitting terminal, a
high-pass circuit is provided to pass signals of higher frequencies
including a tuning frequency of the antenna and to block signals of
frequencies lower than the tuning frequency of the antenna.
18. An antenna device comprising: a conductive earth substrate; an
antenna element having an end connected to said conductive earth
substrate for grounding and formed on a common circuit board; and a
feeding terminal pulled out of said antenna element, characterized
in that a resonant circuit is inserted between said feeding
terminal and the other end of said antenna element which is not
grounded, and said antenna element and said resonant circuit are
located together on one side of said common circuit.
19. The antenna device according to claim 18, characterized in that
said antenna element consists of a plurality of elements and said
resonant circuit is inserted within each of said plurality of
elements in a similar manner.
20. The antenna device according to claim 18 or 19, characterized
in that said resonant circuit is a parallel circuit having an
inductor and a capacitor section.
21. The antenna device according to claim 20, characterized in that
said capacitor section is a series circuit having a capacitor and a
voltage-variable capacitor element.
22. A communication system comprising: an antenna device according
to claim 21; a receiver having a receiving channel setting circuit
which generates a bias voltage for said voltage-variable capacitor
element of said antenna device; and a feeding line for connecting a
signal input section of said receiver to a feeding terminal of said
antenna device, characterized in that said voltage-variable
capacitor element of said antenna device is connected to said
feeding terminal, a direct-current blocking capacitor is provided
between said antenna element and said feeding terminal and at the
input terminal of a receiving amplifier of said receiver,
respectively, and a receiving channel is established by varying the
bias voltage generated by said receiving channel setting
circuit.
23. A communication system comprising: an antenna device having a
conductive earth substrate, an antenna element formed on a common
circuit board located in the proximity of said conductive earth
substrate, and a receiving amplifier provided on said common
circuit board between said antenna element and a feeding terminal;
a receiver having a power supply section to supply electric power
to said receiving amplifier of said antenna device; and a feeding
line for connecting said feeding terminal of said antenna device to
a signal input section of said receiver, characterized in that a
direct-current blocking capacitor is provided between said
receiving amplifier of said antenna device and said feeding
terminal and at the input terminal of a receiving amplifier of said
receiver, respectively, and electric power is supplied by said
power supply section to said receiving amplifier of said antenna
device through said feeding line.
24. The communication system according to claim 23, characterized
in that said receiver comprises a power control section for
controlling said power supply section to turn on/off.
25. A communication system comprising: an antenna device having a
conductive earth substrate, a receiving element having a receiving
terminal formed on a common circuit board located in the proximity
of said conductive earth substrate, a transmitting element having a
transmitting terminal formed on said common circuit board located
in the proximity of said receiving element, and a
transmitting/receiving changeover circuit provided on said common
circuit board and capable of switching said receiving terminal and
said transmitting terminal; a feeding line connected to said
transmitting/receiving changeover circuit; and a communication
device connected to said feeding line and capable of both
transmitting and receiving, characterized in that said
transmitting/receiving changeover circuit of said antenna device is
controlled by using a switch signal to change over to the
transmission operation in said communication device.
26. The antenna device according to claim 1, 18, 23 or 25,
characterized in that the area of said conductive earth substrate
is substantially equal to the external area of said antenna
element.
27. The antenna device according to claim 1, 18, 23 or 25,
characterized in that said conductive earth substrate is provided
in the proximity of and facing the body earth substrate of a
stationary device, mobile device, or automotive vehicle, while
appropriate insulation is kept.
28. The antenna device according to claim 1, 18, 23 or 25,
characterized in that the antenna body is provided at various
important locations on an automobile, train, or airplane.
29. An antenna device comprising: a conductive earth substrate; a
main antenna element connected to said conductive earth substrate
through a first ground connection to be substantially parallel to
said conductive earth substrate; a feeding terminal connected to a
point in said main antenna element wherein a grounding terminal of
said feeding terminal is connected to said first ground connection;
and a passive element connected to said conductive earth substrate
through a second ground connection along said main antenna
element.
30. The antenna device according to claim 29, characterized in that
said main antenna element and said passive element are in a
circular shape when they are taken in a direction substantially
perpendicular to said conductive earth substrate.
31. The antenna device according to claim 29, characterized in that
a ground terminal of a feeding terminal for said main element is
connected to the connection between said main element and said
ground connection.
32. The antenna device according to claim 29, characterized in that
said conductive earth substrate is fixed on a conductive structure
larger than said conductive earth substrate through an insulator
and the size and shape of said conductive earth substrate are equal
to those of said main element or said passive element whichever is
outer.
33. The antenna device according to claim 29, characterized in that
said first ground connection connected to said main element and
said second ground connection connected to said passive element
constitute a single plate-like ground connection.
34. The antenna device according to claim 29, characterized in that
two passive elements are provided, one on each side of said main
element.
35. An antenna device according to claim 29, characterized in that
a plurality of main elements are provided and a common feeding
terminal is connected to said plurality of main elements to enable
band synthesis.
36. The antenna device according to claim 29, characterized in that
said main element and said passive element are patterned at
opposite locations on the face and the back of a printed circuit
board, respectively.
37. A digital television broadcasting receiving device comprising:
input means which is an antenna device according to claim 1, 18,
23, or 29 and converts electromagnetic waves into electric signals;
delay means for receiving a signal from said input means and
delaying it; synthesis means for synthesizing a signal from said
delay means and a signal from said input means; reception means for
performing frequency conversion on a signal from said synthesis
means; and demodulation means for converting a signal from said
reception means into a baseband signal, characterized in that the
delay time used in said delay means and the synthesis ratio used in
said synthesis means can be established arbitrarily.
38. The digital television broadcasting receiving device according
to claim 37, characterized in that said device has a plurality of
antenna elements and each antenna element is installed so that it
can have the maximum gain for an electric wave of different
polarization planes.
39. A digital television broadcasting receiving device comprising:
input means which is an antenna device according to claim 1, 18,
23, 25, or 29 and converts electromagnetic waves into electric
signals; delay means for receiving a signal from said input means
and delaying it; synthesis means for synthesizing a signal from
said delay means and a signal from said input means; reception
means for performing frequency conversion on a signal from said
synthesis means; demodulation means for converting a signal from
said reception means into a baseband signal; delayed wave
estimation means for receiving a signal indicating the demodulation
conditions from said demodulation means and estimating a delayed
wave contained in a signal from said input means; and synthesis
control means for controlling said synthesis means and said delay
means in accordance with a signal from said delayed wave estimation
means, characterized in that either the signal synthesis ratio used
in said synthesis means or the delay time used in said delay means
can be controlled in accordance with a signal from said synthesis
control means.
40. The digital television broadcasting receiving device according
to claim 39, characterized in that said device has a plurality of
antenna elements and each antenna element is installed so that it
can have the maximum gain for an electric wave of different
polarization planes.
41. A digital television broadcasting receiving device comprising:
input means which is an antenna device according to claim 1, 18,
23, 25, or 29 and converts electromagnetic waves into electric
signals; reception means for performing frequency conversion on a
signal from said input means; delay means for receiving a signal
from said reception means and delaying it; synthesis means for
synthesizing a signal from said delay means and a signal from said
reception means; and demodulation means for converting a signal
from said synthesis means into a baseband signal, characterized in
that the delay time used in said delay means and the synthesis
ratio used in said synthesis means can be established
arbitrarily.
42. The digital television broadcasting receiving device according
to claim 41, characterized in that said device has a plurality of
antenna elements and each antenna element is installed so that it
can have the maximum gain for an electric wave of different
polarization planes.
43. A digital television broadcasting receiving device comprising:
input means which is an antenna device according to claim 1, 18,
23, 25, or 29 and converts electromagnetic waves into electric
signals; reception means for performing frequency conversion on a
signal from said input means; delay means for receiving a signal
from said reception means and delaying it; synthesis means for
synthesizing a signal from said delay means and a signal from said
reception means; demodulation means for converting a signal from
said synthesis means into a baseband signal; delayed wave
estimation means for receiving a signal indicating the demodulation
conditions from said demodulation means and estimating a delayed
wave contained in a signal from said input means; and synthesis
control means for controlling said synthesis means and said delay
means in accordance with a signal from said delayed wave estimation
means, characterized in that either the signal synthesis ratio used
in said synthesis means or the delay time used in said delay means
can be controlled in accordance with a signal from said synthesis
control means.
44. The digital television broadcasting receiving device according
to claim 43, characterized in that said device has a plurality of
antenna elements and each antenna element is installed so that it
can have the maximum gain for an electric wave of different
polarization planes.
45. A digital television broadcasting receiving device comprising:
input means which is an antenna device according to claim 1, 18,
23, 25, or 29 and converts electromagnetic waves into electric
signals; reception means for performing frequency conversion on a
signal from said input means; demodulation means for converting a
signal from said synthesis means into a baseband signal; delayed
wave estimation means for receiving information on the demodulation
conditions from said demodulation means and estimating a delayed
wave contained in a signal from said input means; and demodulation
control means for controlling said demodulation means based on
delayed wave information from said delayed wave estimation means,
characterized in that a transfer function to be handled by said
demodulation means is controlled based on a control signal from
said demodulation control means.
46. The digital television broadcasting receiving device according
to claim 45, characterized in that said device has a plurality of
antenna elements and each antenna element is installed so that it
can have the maximum gain for an electric wave of different
polarization planes.
Description
TECHNICAL FIELD
The present invention relates, in particular, to an antenna device
to be attached to a body of an automobile for receiving, for
example, AM, FM, or TV broadcasting or wireless telephone, etc. and
to a communication system using such an antenna device.
BACKGROUND ART
With the advance of the car multimedia era, in addition to an AM/FM
radio, various radio equipments such as a TV receiver, a wireless
telephone set, and a navigation system have been recently installed
in the automobile. Also hereafter, information and services may be
increasingly provided through radio wave and the importance of an
antenna will grow accordingly.
Generally, in the wireless telephone set or any other communication
devices which are used for mobile communication and are capable of
transmitting and receiving, the antenna is used for both
transmitting and receiving and a single terminal connected to that
antenna performs a double function of an input terminal for the
receiving section and an output terminal for the transmitting
section through a common component such as a divider, a mixer, a
circulator, or a switch or the like. During the receiving
operation, such a common component prevents a received signal from
entering the transmitting section through the antenna and allows it
to enter the receiving section properly. On the contrary, during
the transmitting operation, that component prevents a transmission
signal from entering the receiving section from the transmitting
section and allows it to be emitted through the antenna.
As described above, however, when an antenna is used for both
transmitting and receiving with a common component in a
communication device, it may generally require a high costcommon
component and the communication device itself may become very
expensive. In addition, there is a problem that the reception
sensitivity may be degraded with an increased transmission loss by
using a single antenna with a common component.
Moreover, since a receiving amplifier and a transmitting amplifier
are certainly installed at the side of the communication device,
there is a problem that a cable connecting between the antenna and
the communication device may degrade the reception level and the
transmission power.
DISCLOSURE OF THE INVENTION
In view of these problems of conventional antennas, the present
invention aims to provide an antenna device and a communication
system which can improve the reception sensitivity with a reduced
transmission loss and which can be implemented at a lower cost.
Also, the present invention aims to provide an antenna device which
can further improve its gain.
In addition, the present invention aims to provide a digital
television broadcasting receiving device and a receiving method
which can reduce reception disturbance during the mobile reception
of digital data.
A 1st invention of the present invention (corresponding to claim 1)
is an antenna device comprising: a conductive earth substrate; a
receiving element located in the proximity of said conductive earth
substrate and having a receiving terminal; and a transmitting
element located in the proximity of said receiving element and
having a transmitting terminal, characterized in that an end of
said receiving element and an end of said transmitting element are
connected to said conductive earth substrate for grounding through
a common portion and the frequency band of said receiving element
is different from that of said transmitting element.
A 2nd invention of the present invention (corresponding to claim 2)
is an antenna device comprising: a conductive earth substrate; a
receiving element located in the proximity of said conductive earth
substrate and having a receiving terminal; and a transmitting
element located in the proximity of said receiving element and
having a transmitting terminal, characterized in that an end of
said receiving element and an end of said transmitting element are
connected to said conductive earth substrate for grounding at
separate locations and the frequency band of said receiving element
is different from that of said transmitting element.
A 3rd invention of the present invention( corresponding to claim
12) is an antenna device comprising: a conductive earth substrate;
an antenna element having an end connected to said conductive earth
substrate for grounding and formed on a common circuit board; and a
feeding terminal pulled out of said antenna element, characterized
in that a resonant circuit is inserted between said feeding
terminal and the other end of said antenna element which is not
grounded.
A 4th invention of the present invention (corresponding to claim
18) is a communication system comprising: an antenna device having
a conductive earth substrate, an antenna element formed on a common
circuit board located in the proximity of said conductive earth
substrate, and a receiving amplifier provided on said common
circuit board between said antenna element and a feeding terminal;
a receiver having a power supply section to supply electric power
to said receiving amplifier of said antenna device; and a feeding
line for connecting said feeding terminal of said antenna device to
a signal input section of said receiver, characterized in that a
direct-current blocking capacitor is provided between said
receiving amplifier of said antenna device and said feeding
terminal and at the input terminal of a receiving amplifier of said
receiver, respectively, and electric power is supplied by said
power supply section to said receiving amplifier of said antenna
device through said feeding line.
A 5th invention of the present invention (corresponding to claim
20) is a communication system comprising: an antenna device of the
present invention (corresponding to claim 15); a receiver having a
receiving channel setting circuit which generates a bias voltage
for said voltage-variable capacitor element of said antenna device;
and a feeding line for connecting a signal input section of said
receiver to a feeding terminal of said antenna device,
characterized in that said voltage-variable capacitor element of
said antenna device is connected to said feeding terminal, a
direct-current blocking capacitor is provided between said antenna
element and said feeding terminal and at the input terminal of a
receiving amplifier of said receiver, respectively, and a receiving
channel is established by varying the bias voltage generated by
said receiving channel setting circuit.
A 6th invention of the present invention (corresponding to claim
21) is a communication system comprising: an antenna device of the
present invention (corresponding to any one of claims 1 through
10); a communication device having a receiving amplifier and a
transmitting amplifier; a receiving connection line for connecting
the receiving terminal of said antenna device to said receiving
amplifier of said communication device; and a transmitting
connection line for connecting the transmitting terminal of said
antenna device to said transmitting amplifier of said communication
device.
A 7th invention of the present invention (corresponding to claim
22) is a communication system comprising: an antenna device having
a conductive earth substrate, a receiving element having a
receiving terminal formed on a common circuit board located in the
proximity of said conductive earth substrate, a transmitting
element having a transmitting terminal formed on said common
circuit board located in the proximity of said receiving element,
and a transmitting/receiving changeover circuit provided on said
common circuit board and capable of switching said receiving
terminal and said transmitting terminal; a feeding line connected
to said transmitting/receiving changeover circuit; and a
communication device connected to said feeding line and capable of
both transmitting and receiving, characterized in that said
transmitting/receiving changeover circuit of said antenna device is
controlled by using a switch signal to change over to the
transmission operation in said communication device.
A 8th invention of the present invention (corresponding to claim
23) is a communication system comprising: an antenna device of the
present invention (corresponding to claim 11); a communication
device having a power supply section to supply electric power to
said receiving amplifier of said antenna device and capable of both
transmitting and receiving; and a feeding line for connecting a
common terminal of said antenna device to a signal input/output
section of said communication device, characterized in that a
direct-current blocking capacitor is provided between a common
component of said antenna element and said common terminal and at
the input/output terminal of said communication device,
respectively, and electric power is supplied by said power supply
section to a receiving amplifier of said antenna device through
said feeding line.
A 9th invention of the present invention (corresponding to claim
30) is an antenna device comprising: a conductive earth substrate;
a main antenna element connected to said conductive earth substrate
through a first ground connection to be substantially parallel to
said conductive earth substrate; and a passive element connected to
said conductive earth substrate through a second ground connection
along said main antenna element.
A 10th invention of the present invention (corresponding to claim
38) is a digital television broadcasting receiving device
comprising: input means which is an antenna device of the present
invention (corresponding to any one of claims 1 through 37) and
converts electromagnetic waves into electric signals; delay means
for receiving a signal from said input means and delaying it;
synthesis means for synthesizing a signal from said delay means and
a signal from said input means; reception means for performing
frequency conversion on a signal from said synthesis means; and
demodulation means for converting a signal from said reception
means into a baseband signal, characterized in that the delay time
used in said delay means and the synthesis ratio used in said
synthesis means can be established arbitrarily.
A 11th invention of the present invention (corresponding to claim
39) is a digital television broadcasting receiving device
comprising: input means which is an antenna device of the present
invention( corresponding to any one of claims 1 through 37) and
converts electromagnetic waves into electric signals; delay means
for receiving a signal from said input means and delaying it;
synthesis means for synthesizing a signal from said delay means and
a signal from said input means; reception means for performing
frequency conversion on a signal from said synthesis means;
demodulation means for converting a signal from said reception
means into a baseband signal; delayed wave estimation means for
receiving a signal indicating the demodulation conditions from said
demodulation means and estimating a delayed wave contained in a
signal from said input means; and synthesis control means for
controlling said synthesis means and said delay means in accordance
with a signal from said delayed wave estimation means,
characterized in that either the signal synthesis ratio used in
said synthesis means or the delay time used in said delay means can
be controlled in accordance with a signal from said synthesis
control means.
A 12th invention of the present invention (corresponding to claim
40) is a digital television broadcasting receiving device
comprising: input means which is an antenna device of the present
invention (corresponding to any one of claims 1 through 37) and
converts electromagnetic waves into electric signals; reception
means for performing frequency conversion on a signal from said
input means; delay means for receiving a signal from said reception
means and delaying it; synthesis means for synthesizing a signal
from said delay means and a signal from said reception means; and
demodulation means for converting a signal from said synthesis
means into a baseband signal, characterized in that the delay time
used in said delay means and the synthesis ratio used in said
synthesis means can be established arbitrarily.
A 13th invention of the present invention (corresponding to claim
41) is a digital television broadcasting receiving device
comprising: input means which is an antenna device of the present
invention( corresponding to any one of claims 1 through 37) and
converts electromagnetic waves into electric signals, a reception
means for performing frequency conversion on a signal from said
input means; delay means for receiving a signal from said reception
means and delaying it; synthesis means for synthesizing a signal
from said delay means and a signal from said reception means;
demodulation means for converting a signal from said synthesis
means into a baseband signal; delayed wave estimation means for
receiving a signal indicating the demodulation conditions from said
demodulation means and estimating a delayed wave contained in a
signal from said input means; and synthesis control means for
controlling said synthesis means and said delay means in accordance
with a signal from said delayed wave estimation means,
characterized in that either the signal synthesis ratio used in
said synthesis means or the delay time used in said delay means can
be controlled in accordance with a signal from said synthesis
control means.
A 14th invention of the present invention (corresponding to claim
42) is a digital television broadcasting receiving device
comprising: input means which is an antenna device of the present
invention (corresponding to any one of claims 1 through 37) and
converts electromagnetic waves into electric signals; reception
means for performing frequency conversion on a signal from said
input means; demodulation means for converting a signal from said
reception means into a baseband signal; delayed wave estimation
means for receiving information on the demodulation conditions from
said demodulation means and estimating a delayed wave contained in
a signal from said input means; and demodulation control means for
controlling said demodulation means based on delayed wave
information from said delayed wave estimation means, characterized
in that a transfer function to be handled by said demodulation
means is controlled based on a control signal from said
demodulation control means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram showing an example of an antenna
device according to a first embodiment of the present
invention;
FIG. 2 is a schematic diagram showing frequency bands achieved in
the antenna device according to the first embodiment;
FIG. 3 is a schematic diagram showing another example of the
antenna device according to the first embodiment;
FIG. 4 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 5 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 6 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 7 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 8 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 9 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 10 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 11 is as schematic diagram showing still another example of
the antenna device according to the first embodiment;
FIG. 12 is a schematic diagram showing still another example of the
antenna device according to the first embodiment;
FIG. 13 is a schematic diagram showing an example of an antenna
device according to a second embodiment of the present
invention;
FIG. 14 is a schematic diagram showing another example of the
antenna device according to the second embodiment;
FIG. 15 is a schematic diagram showing still another example of the
antenna device according to the second embodiment;
FIG. 16 is a schematic diagram showing still another example of the
antenna device according to the second embodiment;
FIG. 17 is a schematic diagram showing still another example of the
antenna device according to the second embodiment;
FIG. 18 is a schematic diagram showing an example of an antenna
device according to a third embodiment of the present
invention;
FIG. 19 is a schematic diagram for explaining the frequency
characteristics of the antenna device shown in FIG. 18;
FIG. 20 is a schematic diagram showing another example of the
antenna device according to the third embodiment;
FIG. 21 is a schematic diagram for explaining the frequency
characteristics of the antenna device shown in FIG. 20;
FIG. 22 is a schematic diagram showing an example of the main
components in an antenna device according to a fourth embodiment of
the present invention;
FIG. 23 is a schematic diagram for explaining the frequency
characteristics of the antenna device shown in FIG. 22;
FIG. 24 is a schematic diagram showing another example of the main
components in the antenna device according to the fourth
embodiment;
FIG. 25 is a schematic diagram showing an example of the main
components in an antenna device according to a fifth embodiment of
the present invention;
FIG. 26 is a schematic diagram for explaining the frequency
characteristics of the antenna device shown in FIG. 25;
FIG. 27 is a schematic diagram showing the configuration of an
example of a communication system which uses an antenna device
according to a sixth embodiment of the present invention;
FIG. 28 is a schematic diagram showing the configuration of another
example of a communication system which uses the antenna device
according to the sixth embodiment;
FIG. 29 is a schematic diagram showing the configuration of an
example of a communication system which uses an antenna device
according to a seventh embodiment of the present invention;
FIG. 30 is a schematic diagram showing the configuration of an
example of a communication system which uses an antenna device
according to an eighth embodiment of the present invention;
FIG. 31 is a schematic diagram showing the configuration of another
example of a communication system which uses the antenna device
according to the eighth embodiment;
FIG. 32 is a schematic diagram showing the configuration of still
another example of a communication system which uses the antenna
device according to the eighth embodiment;
FIG. 33 is a schematic diagram showing the configuration of an
example of a communication system which uses an antenna device
according to a ninth embodiment of the present invention;
FIG. 34 is a schematic diagram showing the configuration of an
example of a communication system which uses an antenna device
according to the tenth embodiment of the present invention;
FIG. 35 is a schematic diagram showing the configuration of another
example of a communication system which uses the antenna device
according to a tenth embodiment;
FIG. 36 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 37 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 38 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 39 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 40 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 41 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 42 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 43 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 44 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 45 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 46 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 47 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 48 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 49 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 50 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 51 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 52 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 53 shows the positional relationship between an antenna and a
conductive earth substrate according to the present invention;
FIG. 54 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 55 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 56 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 57 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 58 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 59 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 60 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 61 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 62 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 63 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 64 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 65 is a perspective diagram showing possible locations where
an antenna device according to the present invention is to be
installed;
FIG. 66 is a schematic diagram showing an example of a mobile
communication device with an antenna device according to the
present invention;
FIG. 67 is a schematic diagram showing an example of a portable
telephone with an antenna device according to the present
invention;
FIG. 68 shows an example of band synthesis according to the present
invention;
FIG. 69 shows an example of gain accumulation according to the
present invention;
FIG. 70 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 71 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 72 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 73 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 74 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 75 is a perspective diagram showing a possible automobile
application of an antenna device according to the present
invention;
FIG. 76 is a perspective diagram showing possible locations where
an antenna according to the present invention is to be installed
for each part of the automobile;
FIG. 77 is a diagram for explaining the properties of an antenna
according to the present invention;
FIG. 78 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 79 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 80 is a perspective diagram showing possible locations where
an antenna according to the present invention is to be installed
for each part of the automobile;
FIG. 81 is a perspective diagram showing a possible application to
a portable telephone of an antenna according to the present
invention;
FIG. 82 is a perspective diagram showing a possible application to
an ordinary house of an antenna according to the present
invention;
FIG. 83 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 84(a) is a schematic diagram showing the configuration of an
example of an antenna according to the present invention and FIG.
84(b) is an explanatory drawing therefor;
FIG. 85 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 86 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 87 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIGS. 88(a) and 88(b) are schematic diagrams showing the
configuration of an example of an antenna according to the present
invention and FIG. 88(c) is a graph for explaining the frequency
characteristics thereof;
FIGS. 89(a) and 89(b) are schematic diagrams showing the
configuration of an example of an antenna according to the present
invention and FIG. 89(c) is a graph for explaining the frequency
characteristics thereof;
FIGS. 90(a) and 90(b) are schematic diagrams showing the
configuration of an example of an antenna according to the present
invention and FIG. 90(c) is a graph for explaining the frequency
characteristics thereof;
FIG. 91 shows an application of an antenna device according to the
present invention;
FIG. 92 shows an application of an antenna device according to the
present invention;
FIG. 93 shows an application of an antenna device according to the
present invention;
FIG. 94 shows an application of an antenna device according to the
present invention;
FIG. 95 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 96 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 97 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 98 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 99 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 100 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 101 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 102 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 103 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 104 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 105 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 106 is a schematic diagram showing various element patterns
according to the present invention;
FIG. 107 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 108 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 109 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 110 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 111 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 112 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 113 is a perspective view showing a specific configuration of
an antenna device according to the present invention;
FIG. 114 shows the impedance and VSWR characteristics of the
antenna shown in FIG. 113;
FIG. 115 shows the directional gain characteristics of the antenna
shown in FIG. 113;
FIG. 116 shows the VSWR characteristics of an element for
explaining band synthesis in a 4-element antenna;
FIG. 117 shows the VSWR characteristics of another element for
explaining band synthesis in the 4-element antenna;
FIG. 118 shows the VSWR characteristics of another element for
explaining band synthesis in the 4-element antenna;
FIG. 119 shows the VSWR characteristics of another element for
explaining band synthesis in the 4-element antenna;
FIG. 120 shows the VSWR characteristics after band synthesis of the
4-element antenna shown in FIGS. 116 through 119;
FIG. 121 shows the VSWR characteristics when the range of ordinates
in FIG. 120 is extended;
FIG. 122 shows the directional gain characteristics when the
antenna ground is located at different distances from the device
ground in the antenna of FIG. 72(b);
FIG. 123 shows the directional gain characteristics in the antenna
of FIG. 83(a);
FIG. 124 shows the directional gain characteristics in the antenna
of FIG. 83(b);
FIG. 125(a) shows that a low-pass circuit is provided near a
feeding terminal in an antenna device according to the present
invention and FIG. 125(b) shows that a high-pass circuit is
provided near a feeding terminal in a similar manner;
FIG. 126 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 127 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 128 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 129 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 130 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 131 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 132 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 133 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 134 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 135 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 136 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 137 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 138 is a schematic diagram showing an example of an antenna
device according to the present invention;
FIG. 139 shows the gain characteristics o f an example of an
antenna device according to the present invention;
FIG. 140 shows the gain characteristics of an example of an antenna
device according to the present invention;
FIG. 141 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to an embodiment
of the present invention;
FIG. 142 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to another
embodiment of the present invention;
FIG. 143 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to another
embodiment of the present invention;
FIG. 144 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to another
embodiment of the present invention;
FIG. 145 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to another
embodiment of the present invention;
FIG. 146 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to another
embodiment of the present invention;
FIG. 147 is a conceptual diagram showing the result of frequency
analysis performed on a received signal which is affected by
disturbance of a delayed wave;
FIG. 148 is a conceptual diagram showing the gain control performed
by a synthesis means;
FIG. 149 is a conceptual diagram showing the delay time and error
rate of a delayed wave; and
FIG. 150 is a flow chart for explaining antenna switching
conditions for changing over from one antenna to another.
DESCRIPTION OF SYMBOLS
101, 104 Antenna element (linear conductor) 102 Feeding terminal
151 Antenna ground 152 Receiving element 153 Transmitting element
205 Conductive earth substrate 356 Common circuit board 502, 504
Reactance element 1304 Printed circuit board 1357 Receiving
amplifier 1458 Transmitting amplifier 1505 Recess 1655 Common
component 1806 Multilayer printed circuit board 1853 Resonant
circuit loading section 1901 Feeding point 2760 Direct-current
power supply section 2961 Receiving channel setting circuit 3003
Dielectric 3203 Coil 3355 Transmitting/receiving element changeover
relay switch 3362 Handset 3365 Voice modulator 3503 Diversity
changeover switch 3804 Communication device 3805 Body 3902
Shielding case 4603 High-permittivity material 5603, 5606
Ferroelectric 4001 Main element 4002 Passive element 4003
Conductive earth substrate 4004 Ground connection 4005 Ground
connection 4006 Feeding terminal 6001 Input means 6002 Delay means
6003 Synthesis means 6004 Reception means 6005 Demodulation means
6006 Synthesis control means 6007 Delayed wave estimation means
6008 Positional information determination means 6009 Vehicle
information detection means 6011 Antenna 6012 Amplification means
6061 Gain control means 6062 Delay time control means 6091 Speed
detection means 6092 Position detection means
BEST MODE FOR CARRYING OUT THE INVENTION
Now, the present invention will be described below with respect to
the accompanying drawings which show embodiments thereof.
(Embodiment 1)
FIG. 1 includes a plan view and a sectional view showing an antenna
device according to a first embodiment of the present invention.
The antenna device comprises a receiving element 152 and a
transmitting element 153 with their antenna planes facing an
antenna ground (conductive earth substrate) 151, and the receiving
element 152 is provided with a receiving terminal 154 and the
transmitting element 153 is provided with a transmitting terminal
155. As shown in FIG. 2, the resonance frequencies of the receiving
element 152 and the transmitting element 153 are different from
each other, depending on the element lengths, and thus, the
isolation between a received signal and a transmission signal can
be improved. In addition, the receiving element 152 and the
transmitting element 153 have an end connected to the antenna
ground 151 for grounding, respectively. Since the receiving element
152 and the transmitting element 153 operate separately from each
other, the antenna device can be optimized for receiving and
transmitting, respectively and the reception sensitivity and the
transmission efficiency can be improved.
It should be noted that in the Figure, the words in parentheses
indicate the case where the resonance frequencies for transmission
and reception are set inversely but the setting of those
frequencies may be accomplished optionally. This may apply to
succeeding examples.
FIG. 3 shows that in an antenna device having the configuration
similar to that described above, a receiving element 352 and a
transmitting element 353 are formed on a common circuit board 356
provided to face an antenna ground 351, by using a printed-wiring
technique or the like. This antenna device is functionally
equivalent to the antenna device described above, but the stability
-can be improved because the elements are fixed on the common
circuit board 356.
FIG. 4 shows an example that in the configuration of FIG. 3, a
receiving element 452 is formed on the opposite side of a common
double-sided circuit board 456 to a transmitting element 453, that
is, on the side closer to an antenna ground 451. Of course, it
should be noted that the receiving element 452 and the transmitting
element 453 may be formed inversely.
FIG. 5 shows an example that in the configuration of FIG. 3, a
receiving element 552 and a transmitting element 553 are connected
to an antenna ground 551 through separate ground connections (at
different locations) 557. In this example, the receiving element
552 and the transmitting element 553 are separately grounded at one
of their ends farther from each other. Such a configuration can
improve the isolation between a received signal and a transmission
signal as compared with an antenna device with a common ground.
FIG. 6 also shows that separate ground connections are provided but
in this configuration, a receiving element 652 and a transmitting
element 653 are separately grounded at one of their ends closer to
each other.
FIG. 7 shows that an antenna device comprises a receiving element
752 and a transmitting element 753 arranged so that their antenna
planes do not overlap one another, and these elements are
separately grounded at one of their ends closer to each other. The
isolation can be further improved depending on the locations of
these elements. FIG. 8 shows that in the configuration of FIG. 7, a
receiving element 852 and a transmitting element 853 are separately
grounded at one of their ends farther from each other. Moreover,
FIG. 9 shows an example that a receiving element 952 and a
transmitting element 953 are arranged in the same direction and
this antenna device can have the same functions as those described
above.
FIG. 10 shows an example that a receiving element 1052 and a
transmitting element 1053 are arranged symmetrically with respect
to a predetermined point and these elements are separately grounded
at one of their ends farther from each other. FIG. 11 shows that in
the configuration of FIG. 10, a receiving element and a
transmitting element are separately grounded at one of their ends
closer to each other. Moreover, FIG. 12 shows that in the
configuration of FIG. 10, a receiving element 1252 is grounded at
its inner end and a transmitting element 1253 is grounded at its
outer end.
(Embodiment 2)
FIG. 13 includes a plan view and a sectional view showing an
antenna device according to a second embodiment of the present
invention. The antenna device has the configuration of FIG. 3 and a
receiving amplifier 1357 is connected between a receiving element
1352 and a receiving terminal 1354. Since the receiving amplifier
1357 is provided near the receiving element 1352 on a common
circuit board 1356, it can amplify a received signal and then
provide it to the appropriate section through the receiving
terminal 1354. The antenna device can withstand any noise coming
into the feeder and enjoy an improved reception sensitivity.
FIG. 14 shows an example that in addition to the components shown
in FIG. 13, a transmitting amplifier 1458 is provided between a
transmitting element 1453 and a transmitting terminal 1455 on a
common circuit board 1456. This configuration can provide an
improved reception sensitivity as well as a reduced power loss in
the feeder and an improved transmission efficiency.
FIG. 15 shows that in the configuration similar to that of FIG. 13,
a common double-sided circuit board 1556 is used to form a
receiving amplifier 1557 on the opposite side of that board to
antenna elements 1552 and 1553 and the receiving amplifier 1557 is
connected to the receiving element 1552 by the cable running
through a through-hole 1558. This configuration can save the space
because the receiving amplifier 1557 is located between the common
double-sided circuit board 1556 and an antenna ground 1551.
FIG. 16 shows that a common component 1655 is used to provide a
common terminal 1654 which performs a double function of a
receiving terminal and a transmitting terminal and the common
component 1655 such as a divider, mixer, circulator, or switch is
provided on a common circuit board 1656 so that the common terminal
1654 can operate as a feeding terminal for both a receiving element
1652 and a transmitting element 1653. FIG. 17 shows an example that
in addition to the components described above, a receiving
amplifier 1757 is inserted between a receiving element 1752 and a
common component 1755. This configuration can allow simple
connection to a communication device through a single cable because
only one feeding terminal is required.
(Embodiment 3)
FIG. 18 includes a plan view and a sectional view showing an
antenna device according to a third embodiment of the present
invention. In the antenna device, an antenna element 1852 having an
end connected to an antenna ground 1851 for grounding and also
having a feeding terminal 1854 connected thereto is formed on a
common circuit board 1855 located parallel to the antenna ground
1851 and a resonant circuit 1853 is inserted within the antenna
element 1852. The resonant circuit 1853 has an appropriate inductor
1856 and a capacitor 1857 connected in parallel so that the circuit
can have an impedance jX1.about.jX2 for a frequency f1.about.f2. As
shown in FIG. 19, the resonant circuit 1853 can provide an antenna
which has a bandwidth of f1.about.f2, because the circuit has an
impedance varying within the range of jX1.about.jX2 and a gain peak
at a frequency f1.about.f2 when the L/C resonance frequency is set
to f0.
FIG. 20 shows that the capacitor of the resonant circuit in FIG. 18
is replaced by a series connection of a fixed direct-current
blocking capacitor 2055 and a voltage-variable capacitance element
(varicap) 2057. As shown in the right of the figure, the
voltage-variable capacitance element 2057 has a capacitance Cv
varying with the bias voltage V and the capacitance and thus the
resonance frequency can be controlled by varying the bias voltage.
As shown in FIG. 21, at a lower bias voltage of the varicap, the
L/C resonance frequency is lowered (f01), the loading reactance jX
increases (jX21.about.jX22), and the antenna tuning frequency is
lowered (f1). On the contrary, at a higher bias voltage of the
varicap, the L/C resonance frequency is raised (f02), the loading
reactance jX decreases (jX11.about.jX12), and the antenna tuning
frequency is raised (f2). Like this, according to the present
embodiment, the tuning frequency can be changed by controlling the
bias voltage of the voltage-variable capacitance element (varicap)
2057.
(Embodiment 4)
FIG. 22 is a schematic diagram showing the configuration of the
main components in an antenna device according to a fourth
embodiment of the present invention. Namely, in the present
embodiment, a resonant circuit (trap circuit) having a
predetermined resonance frequency is inserted in an antenna element
and near a feeding terminal in each antenna device described above.
In FIGS. 22 and 23, a trap circuit 1 (f1) 2252 inserted in an
antenna element 2251 and a trap circuit 3 (f1) 2254 inserted near a
feeding terminal 2255 have a resonance frequency in the
transmission band and another trap circuit 2 (f2) 2253 inserted in
the antenna element 2251 has a resonance frequency in the other
band f2 opposite to the transmission band f1 with respect to the
reception band f0. Therefore, the isolation between antenna
elements with in a certain band can be improved by providing trap
circuits each having a resonance frequency in the frequency band on
each side of the reception frequency.
The trap circuit near the feeding terminal is inserted between the
feeding terminal and the antenna element in FIG. 22 but as shown in
FIGS. 24(a) and (b), a feeding terminal 2453 may be pulled out of a
point between capacitors or in an inductor of a trap circuit 2452
or 2462 inserted in an antenna element 2451. Also, as shown in FIG.
24(c), a trap circuit 2472 may be inserted between a feeding
terminal 2453 and an antenna ground and at a location closer to the
ground. Therefore, when the trap circuit is located closer and
closer to the ground, the inductor value and thus the size of the
trap circuit can be reduced and thereby, a more compact and
lightweight antenna can be provided.
(Embodiment 5)
FIG. 25 is a schematic diagram showing the configuration of the
main components in an antenna device according to a fifth
embodiment of the present invention. Namely, in the present
embodiment, a band-pass circuit having the same resonance frequency
as that of the resonance frequency of the antenna (f0) is inserted
in an antenna element and near a feeding terminal in each antenna
device described above. The band-pass circuit comprises a series
connection of an inductor and a capacitor and both a band-pass
circuit 1 (f0) 2552 inserted in an antenna element 2551 and a
band-pass circuit 2 (f0) 2553 inserted near a feeding terminal 2554
have a reactance characteristic as shown in FIG. 26(a). Thus, as
shown in FIG. 26(b), when a band-pass circuit is inserted, the
selectivity of the antenna can be improved as compared with the
antenna having antenna elements alone and thereby, a higher
selectivity can be achieved.
As shown in FIGS. 125(a) and (b), a low-pass circuit or a high-pass
circuit may be inserted between an antenna element and a feeding
terminal.
In FIG. 125(a), a low-pass circuit 102 is provided between an
antenna element 101 and a feeding terminal 103. When the low-pass
circuit 102 passes signals of lower frequencies including a tuning
frequency of the antenna and blocks signals of frequencies higher
than the tuning frequency of the antenna, the antenna can be
protected against any interference with those signals of
frequencies higher than the tuning frequency of the antenna.
Therefore, any interference can be avoided if the tuning frequency
of another element located in the proximity of the above-mentioned
element is higher than that of the latter element. In FIG. 125(b),
a high-pass circuit 105 is provided between an antenna element 101
and a feeding terminal 103. When the high-pass circuit 105 passes
signals of higher frequencies including a tuning frequency of the
antenna and blocks signals of frequencies lower than the tuning
frequency of the antenna, the antenna can be protected against any
interference with those signals of frequencies lower than the
tuning frequency of the antenna. Therefore, any interference can be
avoided if the tuning frequency of another element located in the
proximity of the above-mentioned element is lower than that of the
latter element.
It should be noted that the low-pass circuit or the high-pass
circuit comprises a capacitor and an inductor in FIG. 125 but other
configurations may be used if similar characteristics can be
accomplished.
(Embodiment 6)
FIG. 27 is a schematic diagram showing the configuration of a
communication system which uses an antenna device according to a
sixth embodiment of the present invention. In the antenna device of
FIG. 27, an antenna element 2752 is formed on a common circuit
board 2755 located parallel to an antenna ground 2751 and a
receiving amplifier 2754 and a direct-current blocking capacitor
2757 are provided between the antenna element 2752 and a feeding
terminal 2753 on the common circuit board 2755. The feeding
terminal 2753 and the power terminal of the receiving amplifier
2754 are connected through a direct-current power supply line
2756.
On the other hand, in a receiver 2759 which is a communication
device, a direct-current power supply section 2760, a receiving
amplifier 2761 and the like are provided to supply a direct-current
power to the receiving amplifier 2754 of the antenna and a
direct-current blocking capacitor 2762 is provided near the input
terminal of the receiving amplifier 2761. The feeding terminal 2753
of the antenna and the receiver 2759 are connected through a
coaxial cable 2758.
In this configuration, a DC signal 2764 is supplied by the
direct-current power supply section 2760 of the receiver 2759 to
the receiving amplifier 2754 of the antenna through the coaxial
cable 2758. At this time, the direct-current blocking capacitors
2757 and 2762 prevent any DC signal from going into the output
terminal of the receiving amplifier 2754 and the input terminal of
the receiving amplifier 2761, respectively. A wave received by the
antenna element 2752 is amplified by the receiving amplifier 2754
and its RF signal 2763 is supplied to the receiving amplifier 2761
of the receiver 2759 through the coaxial cable 2758.
From the foregoing, since the received signal is amplified by the
receiving amplifier 2754 before being supplied to the receiver, the
RF signal passing through the coaxial cable 2758 will have a
sufficient strength and any influence of out side noise can be
reduced to improve the receiving sensitivity. In addition, since
the antenna has the receiving amplifier 2754, the amplifier of the
receiver 2759 can be simplified.
FIG. 28 shows that in addition to the components shown in FIG. 27
described above, a receiving amplifier controller 2861 is provided
to control the power supply from a direct-current power supply
section 2860 to a receiving amplifier 2854 of the antenna. Other
components are identical to those shown in FIG. 27. Therefore,
since the power supply from the direct-current power supply section
2860 to the receiving amplifier 2854 of the antenna can be
controlled by the receiving amplifier controller 2861 to continue
or stop, this configuration can prevent an undesired jamming
signal, if any, from being amplified and supplied to the receiver
2859.
(Embodiment 7)
FIG. 29 is a schematic diagram showing the configuration of a
communication system which uses an antenna device according to a
seventh embodiment of the present invention. In the antenna device
of FIG. 29, an antenna element 2952 is formed on a common circuit
board 2957 located parallel to an antenna ground 2951 and a
variable resonant circuit loading section 2954 consisting of an
inductor 2955, a (voltage) variable capacitance element 2956 and
the like (see FIG. 20) are inserted in the antenna element 2952.
The cathode of the variable capacitance element 2956 and a feeding
terminal 2953 are connected and a direct-current blocking capacitor
2958 is provided near the feeding terminal 2953.
On the other hand, in a receiver 2960 which is a communication
device, a receiving channel setting circuit (tuning channel control
direct-current voltage generator) 2961, a tuner 2962 and the like
are provided to supply a bias voltage to the variable capacitance
element 2956 of the antenna and a direct-current blocking capacitor
2963 is provided near the input terminal of the tuner 2962. The
feeding terminal 2953 of the antenna and the receiver 2960 are
connected through a coaxial cable 2959. It should be noted that the
receiving channel setting circuit 2961 has a function to generate a
voltage corresponding to a capacitance which can provide a desired
tuning frequency and that, for example, it has a predetermined
voltage setting for each channel to generate a voltage according to
a selected channel.
In such a configuration, a variable capacitance element bias
voltage 2965 determined for each channel is applied by the
receiving channel setting circuit 2961 to the variable capacitance
element 2956 through the coaxial cable 2959. Thus, as described
above for FIG. 21, the capacitance varies and the tuning frequency
of the antenna is adjusted to the frequency of the selected
channel. Then a channel signal matching the tuning frequency of the
antenna is supplied to the receiver 2960 through the coaxial cable
2959 as a received RF signal 2964 at the maximum gain.
(Embodiment 8)
FIG. 30 is a schematic diagram showing the configuration of a
communication system which uses an antenna device according to an
eighth embodiment of the present invention. The antenna device of
FIG. 30 is identical to that of FIG. 3 described above. Namely, in
the antenna device, a receiving element 3052 and a transmitting
element 3053 are formed on a common circuit board 3056 located
parallel to an antenna ground 3051 and the receiving element 3052
and the transmitting element 3053 are provided with a receiving
terminal 3054 and a transmitting terminal 3055, respectively.
On the other hand, a communication device 3059 comprises receiving
amplifier 3060, a transmitting amplifier 3061 and the like and the
receiving terminal 3054 of the antenna and the receiving amplifier
3060 are connected through a receiving coaxial cable 3057 as well
as the transmitting terminal 3055 and the transmitting amplifier
3061 are connected through a transmitting coaxial cable 3058.
This configuration can eliminate a generally expensive and heavy
common component which may cause a large passage loss and it can
provide a lightweight and sensitive device at a lower cost.
FIG. 31 shows that in the configuration similar to that of FIG. 30
described above, a receiving amplifier is provided near a receiving
terminal in an antenna device and other components are identical to
those of FIG. 30. Namely, this example uses the same antenna device
as shown in FIG. 13 to use no common component. In addition, the
receiving sensitivity can be improved (for example, more than
approximately 6 dB) and a receiving amplifier which would be
otherwise provided at the initial stage of a communication device
can be eliminated.
FIG. 32 shows that in the configuration of FIG. 31 described above,
a transmitting amplifier is provided near a transmitting terminal
in an antenna device and other components are identical to those of
FIG. 31. Namely, this example uses the same antenna device as shown
in FIG. 14 to use no common component. In addition, the receiving
sensitivity can be improved (for example, more than approximately 6
dB) and a receiving amplifier which would be otherwise provided at
the initial stage of a communication device can be eliminated.
Moreover, a reduced transmission loss can be achieved and a
transmitting amplifier in the communication device can be also
eliminated.
(Embodiment 9)
FIG. 33 is a schematic diagram showing the configuration of a
communication system which uses an antenna device according to a
ninth embodiment of the present invention. The antenna device of
FIG. 33 is basically identical to that of FIG. 3 described above
but a transmitting/receiving element changeover relay switch 3355
is additionally provided. Namely, in the antenna device, a
receiving element 3352 and a transmitting element 3353 are formed
on a common circuit board 3356 located parallel to an antenna g
round 3351 and the receiving terminal of the receiving element 3352
and the transmitting terminal of the transmitting element 3353 are
connected to a feeding terminal 3354 through the
transmitting/receiving element changeover relay switch 3355.
On the other hand, a communication device 3358 comprises a voice
modulator 3365, a common component 3361, a receiving amplifier
3359, a transmitting amplifier 3061[sic] and the like, and it has
also a handset 3362 used for transmission. The handset 3362
comprises a microphone 3364 and a press-to-talk switch 3363, which
is connected to the voice modulator 3365 and a drive coil of the
transmitting/receiving element changeover relay switch 3355 in the
antenna and which is pressed to connect to a direct-current power
supply 3368. The feeding terminal 3354 of the antenna and an
input/output terminal of the communication device 3358 (a common
terminal of the common component 3361) are connected through a
coaxial cable 3357.
In this configuration, the transmitting/receiving element
changeover relay switch 3355 is connected to the receiving element
3352 during a receiving operation and it becomes the transmitting
element 3353 during a transmitting operation, that is, when the
press-to-talk switch 3363 is pressed to energize the coil of the
transmitting/receiving element changeover relay switch 3355. Since
both a received RF signal 3366 and a transmission RF signal 3367
pass through the coaxial cable 3357, the antenna and the
communication device can be connected through such a single coaxial
cable. It should be noted that the common component 3361 of the
communication device 3358 may be implemented by a switch similar to
the transmitting/receiving element changeover relay switch 3355 for
interlocking. It should be also noted that a general signal input
device (such as a digital signal input device) and a modulator
(such as a digital modulator) may be substituted for the microphone
3364 and the voice modulator 3365.
(Embodiment 10)
FIG. 34 is a schematic diagram showing the configuration of a
communication system which uses an antenna device according to a
tenth embodiment of the present invention. The antenna device of
FIG. 34 is basically identical to that of FIG. 17 described above.
Namely, in the antenna device, a receiving element 3452 and a
transmitting element 3453 are formed on a common circuit board 3456
located parallel to an antenna ground 3451 and the transmitting
terminal of the transmitting element 3453 is connected to a common
component 3457 provided on the common circuit board 3456.
Similarly, the receiving element 3452 is connected to the common
component 3457 through a receiving amplifier 3455 provided on the
common circuit board 3456. In addition, the common terminal of the
common component 3457 is connected to a feeding terminal 3454
through a direct-current blocking capacitor 3459. The power
terminal of the receiving amplifier 3455 is connected to the
feeding terminal 3454 through a direct-current power supply line
3458.
On the other hand, a communication device 3461 comprises a common
component 3465, a receiving amplifier 3462 and a transmitting
amplifier 3463 connected to the common component 3465, a modulator
3464 connected to the transmitting amplifier 3463, a receiving
amplifier direct-current power supply section 3467 and the like,
and a direct-current blocking capacitor 3466 is provided between
the common terminal of the common component 3465 and the
input/output terminal of the communication device 3461. The feeding
terminal 3454 of the antenna and the communication device 3461 are
connected through a coaxial cable 3460.
In this configuration, receiving amplifier direct-current power
3470 of the receiving amplifier 3455 of the antenna is supplied
from the receiving amplifier direct-current power supply section
3467 through the coaxial cable 3460. A received RF signal 3468
amplified by the receiving amplifier 3455 is supplied to the
communication device 3461 through the coaxial cable 3460 and then
to the receiving amplifier 3462 of the communication device 3461
through the common component 3465. A transmission RF signal 3469
from the transmitting amplifier 3463 of the communication device
3461 is supplied to the feeding terminal 3454 of the antenna
through the common component 3465 and then emitted by the
transmitting element 3453 through the common component 3457.
FIG. 35 shows that a handset 3565 used for transmission is added to
the configuration of FIG. 34 described above and the handset 3565
comprises a microphone 3567 and a press-to-talk switch 3566, which
is connected to a voice modulator 3564 and a receiving amplifier
direct-current power supply section 3568 and which is pressed to
connect to a direct-current power supply 3574.
In this configuration, during a receiving operation, receiving
amplifier direct-current power 3573 is supplied from the receiving
amplifier direct-current power supply section 3568 to a receiving
amplifier 3555 of the antenna to operate the receiving amplifier
3555. During a transmitting operation, when the press-to-talk
switch 3566 is pressed, the power supply from the receiving
amplifier direct-current power supply section 3568 is stopped or
decreased to a lower level to stop the operation of the receiving
amplifier 3555 of the antenna or to reduce the degree of
amplification. This can prevent the power from being supplied when
unnecessary and the like.
It should be noted that, according to the present embodiment, the
area of the antenna ground facing the antenna elements is shown to
be smaller than the external area of the antenna elements but it is
preferable that the area of the antenna ground is almost equal to
the external area of the antenna elements.
It should be also noted that, according to the present embodiment,
how or where the antenna device is to be installed is not described
above. However, the antenna device may be installed with the
antenna ground located in the proximity of and facing the body
ground of any of various stationary devices, mobile devices,
automotive vehicles or the like as long as appropriate insulation
can be kept. For example, stationary devices include a house or a
building, a fixed communication device and the like, mobile devices
include a portable communication device, a portable telephone set
and the like, and automotive vehicles include an automobile, a
train, an airplane, a ship and the like.
It should be further noted that the shape and number of elements in
the antenna device described above according to the present
embodiment are shown for exemplary purpose only and they are not
limited to those shown in the figures.
Now, how and where the antenna devices described above are to be
installed or the shape, number of antennas and the like applicable
to the antenna devices according to the present invention will be
specifically described below with reference to the drawings.
FIG. 36(a) shows an antenna device which comprises an antenna
element 201 configured by a linear conductor with two bends and
located in the proximity to a conductive earth substrate 205 with
the antenna plane parallel to the substrate, a feeding terminal 202
provided in place on the antenna element 201, and an end 203
connected to the conductive earth substrate 205 for grounding. FIG.
36(b) shows another antenna device which comprises an antenna
element 204 configured by a linear conductor with four bends and
located in the proximity to a conductive earth substrate 205 with
the antenna plane parallel to the substrate, a feeding terminal 202
provided in place on the antenna element 204, and an end 203
connected to th conductive earth substrate 5 for grounding. In this
way, the antenna devices can reduce the installation area as well
as improve their directional gain performance because the antenna
devices are located in the proximity to the conductive earth
substrates 205 with their antenna planes parallel to the conductive
earth substrates 205. It should be noted that the number of bends
in an antenna element is not limited to that described with respect
to the above example. This may also apply to succeeding embodiments
described below.
A specific configuration of the antenna device of FIG. 36(a) is
shown in FIG. 113. In FIG. 113, an antenna element 8501 configured
by a linear conductor with two bends is located at a distance from
a conductive earth substrate 8504 with the antenna plane almost
parallel to the substrate and an end of the antenna element 8501 is
connected to an end of a conductive plate 8503 provided almost
perpendicular to the conductive earth substrate 8504 for antenna
grounding. It should be noted that, in this case, the area formed
by the antenna element 8501 is almost equal to that of the
conductive earth substrate 8504. It should be also noted that a
feeding section 8502 is provided in the way of the antenna element
8501.
The conductive plate 8503 has a width sufficiently larger than that
of the antenna element 8501, that is, a width which may not be
practically affected by any reactance determined from the tuning
frequency of the antenna element 8501. This allows the conductive
plate to serve as a ground. A smaller width may cause the
conductive plate to couple to the antenna element 8501 and thus to
form a single antenna element as a whole together with the antenna
element 8501, which will deviate from the scope of the present
invention. The antenna element 8501 is, for example, 220 mm long
and 2 mm wide for a wavelength of 940 mm and this may make the
antenna device more compact. It should be noted that the antenna
plane and the conductive earth substrate plane may be tilted to the
extent that there exists an effective potential difference between
the antenna element and the substrate. It should be also noted that
if the area of the conductive earth substrate is larger than that
of the antenna plane (for example, by quadruple), the gain may
remain unchanged for a vertically polarized wave but decrease for a
horizontally polarized wave.
The antenna described above differs from conventional antennas in
that, for example, a smaller distance between the antenna element
and the ground plate may degrade the performance of a conventional
inverted F-shaped antenna, while such a smaller distance may
improve the performance of the antenna device according to the
present invention.
The impedance and VSWR characteristics of the antenna of FIG. 113
are shown in FIG. 114. Its directional gain characteristics are
shown in FIG. 115. As shown in FIG. 115, the antenna of FIG. 113
has a generally circular directivity with respect to a vertically
polarized wave.
Needless to say, the shape and number of antenna elements are not
limited to those described with respect to the above example.
It should be more preferable that the distance between the
conductive earth substrate and the antenna element is a fortieth of
the wavelength or more.
FIG. 37(a) shows an antenna device which comprises an antenna
element 401 configured to be a dipole antenna configured by a
linear conductor with four bends and located in the proximity to a
conductive earth substrate 405 with the antenna plane parallel to
the substrate, a feeding terminal 402 provided in place on the
antenna element 401, and a point 403 connected to the conductive
earth substrate 405 for grounding. FIG. 37(b) shows another antenna
device which comprises an antenna element 404 configured by being
be a dipole antenna configured by a linear conductor with eight
bends and located in the proximity to a conductive earth substrate
405 with the antenna plane parallel to the substrate, a feeding
terminal 402 provided in place on the antenna element 401, and a
point 403 connected to the conductive earth substrate 405 for
grounding. In this way, the antenna devices according to the
present embodiment can reduce the installation area as well as
further improve their directional gain performance when the antenna
devices are located in the proximity to the conductive earth
substrates with their antenna planes parallel to the conductive
earth substrates 405, respectively.
FIG. 38(a) shows an antenna device which comprises three monopole
antenna elements 601a, 601b, and 601c having two bends and
different lengths and being located on the same plane in the
proximity to a conductive earth substrate 607, and reactance
elements 602a, 602b, 602c, and 604 connected between the taps of
the antenna elements 601a, 601b, and 601c and a feeding terminal
603 and between the feeding terminal 603 and a ground terminal 605,
respectively, to adjust their impedance. FIG. 38(b) shows another
antenna device which substitutes antenna elements 606a, 606b, and
606c having four bends for the antenna elements 601a, 601b, and
601c of the antenna device of FIG. 38(a) described above.
With the configurations described above, an antenna device having a
desirable bandwidth can be implemented by setting the tuning
frequencies of the antenna elements at regular intervals. FIG. 68
shows an example of band synthesis performed by an antenna having
seven antenna elements and it may be seen from the figure that a
broadband frequency characteristic can be achieved through such
band synthesis even when each antenna element has only a small
bandwidth.
Specific examples of such band synthesis are described with respect
to the VSWR characteristics shown in FIGS. 116 through 121. Namely,
these examples use four antenna elements with different tuning
frequencies, that is, 196.5 MHz (FIG. 116), 198.75 MHz (FIG. 117)
200.5 MHz (FIG. 118), and 203.75 MHz (FIG. 119), respectively. FIG.
120 so shows the VSWR characteristics after band synthesis of these
antenna elements and it can be seen that the band has become wider
than before. FIG. 121 shows the VSWR characteristics when the range
of ordinates in FIG. 120 is extended (by quintuple)
FIG. 39(a) shows that additional reactance elements 808a and 808b
for band synthesis are provided between antenna elements 801a,
801b, and 801c in an antenna device having the configuration
similar to that of FIG. 38(a) described above. FIG. 39(b) shows
that additional reactance elements 808a and 808b for band synthesis
are provided between antenna elements 806a, 806b, and 806c in an
antenna device having the configuration similar to that of FIG.
38(b) described above.
FIG. 40(a) shows an antenna device which comprises three dipole
antenna elements 1001, 1002, and 1003 having four bends and
different lengths and being located on the same plane in the
proximity to a conductive earth substrate 1007, and reactance
elements 1004, 1005, 1006, and 1009 connected between the taps of
the antenna elements 1001, 1002, and 1003 and a feeding terminal
1008 and between the feeding terminal 1008 and a ground terminal
1010, respectively, to adjust their impedance. FIG. 40(b) shows
another antenna device which substitutes antenna elements 1011,
1012, and 1013 having eight bends for the antenna elements 1001,
1002, and 1003 of the antenna device of FIG. 40(a) described
above.
FIG. 41(a) shows that additional reactance elements 1214, 1215,
1216, and 1217 for band synthesis are provided between antenna
elements 1201, 1202, and 1203 at two separate locations in an
antenna device having the configuration similar to that of FIG.
40(a) described above. FIG. 41(b) shows that additional reactance
elements 1214, 1215, 1216, and 1217 for band synthesis are provided
between antenna elements 1211, 1212, and 1213 at two separate
locations in an antenna device having the configuration similar to
that of FIG. 40(b) described above.
FIG. 42(a) shows an antenna device which comprises three dipole
antenna elements 1301, 1302, and 1303 having different lengths and
being formed on a printed circuit board 1304. FIG. 42(b) shows
another antenna device of the configuration similar to that of FIG.
42(a) described above, which has a conductive earth substrate 1308
formed on the opposite side of the printed circuit board 1304 to
the antenna element 1320. Such a configuration where a printed
circuit board is used to form the antenna elements 1301, 1302, and
1303 (1305, 1306, 1307) and the conductive earth substrate 1308 can
save the space necessary for an antenna device as well as allow
easy fabrication of the antenna device with improved performance
reliability and stability.
FIG. 43 shows that antenna devices of the configurations similar to
those of FIG. 42(a) described above have a conductor for band
analysis formed on the opposite side of a printed circuit board to
antenna elements in a direction perpendicular to the antenna
elements. Namely, FIG. 43(a) shows an antenna device which
comprises three dipole antenna elements 1401, 1402, and 1403 having
different lengths and being formed on a printed circuit board 1404
and two conductors 1405 formed on the opposite side of the printed
circuit board 1404 to the antenna element 1410 in a direction
perpendicular to the antenna element. FIG. 43(b) shows another
antenna device of the configuration similar to that of FIG. 43(a)
described above, which has a conductive earth substrate 1406
located in close proximity on the opposite side to the antenna
element 1410. This conductive earth substrate 1406 may be formed on
the printed circuit board by using a multilayer printing technique.
The configuration described above can allow easy fabrication of
elements for band synthesis.
FIG. 44 shows an antenna device which has antenna elements 1501,
1502, and 1503 located within a recess 1505 in a conductive earth
substrate 1504. This configuration can eliminate any protrusion
from an automobile body and improve the directional gain
performance through interaction between the edge of the antenna
element 1510 and the conductive earth substrate 1504 .
The antenna device of FIG. 45(a) comprises an antenna 1610
consisting of antenna elements 1601, 1602, and 1603 and an antenna
1620 consisting of antenna elements 1606, 1607, and 1608 and these
antennas 1610 and 1620 are located in the same plane and within a
recess 1605 in a conductive earth substrate 1604. It should be
noted that the antennas 1610 and 1620 of this example are different
from each other in size and shape but they may be of the same size
and shape. Feeding sections of these antennas are located in the
proximity of each other. FIG. 45(b) shows that a similar antenna is
located in the proximity of a planar conductive earth substrate
1609.
The antenna device of FIG. 46(a) comprises an upper antenna 1710
consisting of antenna elements 1701, 1702, and 1703 and a lower
antenna 1720 also consisting of antenna elements 1701, 1702, and
1703 and these antennas 1710 and 1720 are located at two levels and
within a recess 1705 in a conductive earth substrate 1704. It
should be noted that the antennas 1710 and 1720 of this example are
of the same size and shape but they may be different from each
other in size and shape. FIG. 46(b) shows that a similar antenna is
located in the proximity of a planar conductive earth substrate
1706. If the antennas are of the same size, they will have the same
tuning frequency. Therefore, the bandwidth of the whole antenna
device is the same as that of a single element but this example can
implement a high-gain and high-selectivity antenna because the
overall gain of the antenna element can be improved as compared
with a single-element implementation by accumulating the gain of
each antenna element, as shown FIG. 69.
The antenna device of FIG. 47(a) comprises three antennas 1801,
1802, and 1803 each having one or more bends and a plurality of
dipole antenna elements and these antennas are formed to be a
multilayer printed circuit board 1806 and located with in a recess
1805 in a conductive earth substrate 1804. It should be noted that
the three antennas 1801, 1802, and 1803 of this example are of the
same size and shape but they may be different from each other in
size and shape. It should be also noted that the three antennas are
layered in this example but four or more antennas maybe layered.
FIG. 47(b) shows that a similar antenna is located in the proximity
of a planar conductive earth substrate 1807. As described above, a
high-gain and high-selectivity antenna can be implemented easily by
forming a plurality of antennas as a multilayer printed circuit
board.
The antenna of FIG. 48 has two linear conductors each having four
bends and these conductors are located opposite to each other with
respect to a feeding section. Namely, FIG. 48(a) shows an antenna
device which has two linear conductors 1902 and 1903 bending in
opposite directions to each other with respect to a feeding point
1901 and FIG. 48(b) shows another antenna device which has two
linear conductors 1904 and 1905 bending in the same direction with
respect to a feeding point 1901. This shape can allow
implementation of a compact planar nondirectional antenna.
On the other hand, FIG. 49(a) shows an antenna device having an
antenna element 2002 in which the length between a feeding section
2001 and a first bend P is relatively longer than the length
between the first bend P and a second bend Q. FIG. 49(b) shows an
antenna device having an antenna element 2002 in which the length
between a feeding section 2001 and a first bend P is relatively
shorter than the length between the first bend P and a second bend
Q. This shape can allow the antenna device to be installed in a
narrow area.
It should be noted that this example has two linear conductors
located opposite to each other with respect to a feeding section
but the number of linear conductors is not limited to that of this
example and may be only one. In addition, the number of bends is
not limited to that of this example.
It should be noted that this example has two linear conductors
located opposite to each other with respect to a feeding section
but the number of linear conductors is not limited to that of this
example and may be only one. In addition, the number of bends is
not limited to that of this example.
It should be also noted that the linear conductors in this example
are bent but they maybe curved or spiralled. For example, as shown
in FIG. 50(a), this example may have two linear conductors 2102 and
2103 curving in opposite directions to each other with respect to a
feeding section 2101 or two linear conductors 2104 and 2105 curving
in the same direction with respect to a feeding section 2101. Also,
as shown in FIG. 50(b), this example may have two linear conductors
2106 and 2107 spiralling in opposite directions to each other with
respect to a feeding section 2101 or two linear conductors 2108 and
2109 spiralling in the same direction with respect to a feeding
section 2101.
When an antenna of this example is fabricated, an antenna element
can be formed, of course, by working metal members but it may be
formed through printed-wiring on a circuit board. Such a
printed-wiring technique can allow greatly easy fabrication of an
antenna, thereby to expect reducing cost, providing a more compact
antenna, improving reliability and the like.
The antenna device of FIG. 51 is located in the proximity of a
conductive earth substrate with its ground terminal connected to
the substrate. For example, as shown in FIG. 51(a), an antenna
element 2201 is located in the proximity of a substrate 2204 with
its ground terminal 2203 connected to the substrate 2204. It should
be noted that this antenna device is similar to that of FIG. 3(b)
described above but differs therefrom in that a feeding terminal
2202 is provided on the opposite side of the conductive earth
substrate 2204 to the antenna device by running the cable through
the substrate. Such a configuration can provide a desired impedance
characteristic and directivity.
FIG. 51(b) shows that a switching element is provided between a
ground terminal and a conductive earth substrate in the antenna. As
shown in the figure, a switching element 2205 is provided between a
ground terminal 2203 of an antenna element 2201 and a conductive
earth substrate 2204 to select which state, that is, whether or not
the ground terminal is connected to the conductive earth substrate
can effect the optimum radio-wave propagation. For this purpose,
the switching element 2205 may be remotely operated to control the
antenna device depending on the state of a received wave. The
antenna device of this example is used for a vertically polarized
wave if the ground terminal 2203 is connected to the substrate,
while it is used for a horizontally polarized wave if the ground
terminal is not connected to the substrate.
It should be noted that the feeding terminal 2202 penetrates the
conductive earth substrate 2204 in FIG. 51(b) but its location is
not limited to this example and that, as shown in FIG. 52, a
feeding terminal 2302 and a ground terminal 2303 may be not to
penetrate the conductive earth substrate 2304.
FIG. 53 shows the positional relationship between the antenna and
the conductive earth substrate in the antenna device described
above. As shown in FIG. 53(a), a conductive earth substrate 2402
and an antenna 2401 are located parallel to each other at a
distance of h. The directivity of the antenna 2401 can be changed
to a desired direction by controlling the distance h. The tuning
frequency is raised if the antenna 2401 is closer to the conductive
earth substrate 2402, while the tuning frequency is lowered if the
antenna is more distant from the substrate. Therefore, the antenna
device may be configured to control the distance h depending on the
state of a received wave. The control of the distance h may be
accomplished, for example, by using a feed or slide mechanism (not
shown) to move the antenna 2401 in a direction perpendicular to the
antenna plane or by inserting an insulation spacer (not shown)
between the antenna 2401 and the conductive earth substrate 2402
and moving the spacer in a direction parallel to the antenna plane
to adjust the length of the spacer insertion. Also, the size of the
spacer maybe determined to obtain a desired antenna performance
during the fabrication of the antenna. It should be noted that a
spacer between the substrate and the antenna may be made of a
low-permittivity material such as expanded styrol.
As shown in FIG. 53(b), the conductive earth substrate 2402 and the
antenna 2403 may be located to form a predetermined angle .theta.
(in this case, 90 degrees) between them. The directivity of the
antenna 2403 can be controlled by adjusting the angle .theta.
through a hinge mechanism and the like.
It should be further noted that the number of antenna elements is
one according to the present embodiment but it is not limited to
this example and may be two or more. It should be also noted that
the substrate consists of a single conductor in this example but
the body of an automobile and the like may be used as the
substrate.
FIG. 54 shows that an antenna consists of a plurality of antenna
elements arranged in a predetermined range and served by a single
feeding mechanism. As shown in FIG. 54(a), a plurality of antenna
elements 2501, 2502, and 2503 are served by a single feeding
mechanism to provide an antenna consisting of the group of antenna
elements. For example, a broadband antenna which covers a desired
bandwidth as a whole can be implemented by covering a different
bandwidth with each of the antenna elements. Particularly, in the
arrangement of FIG. 54(a), the outer antenna element 2501 is
necessarily longer than the inner antenna element 2503 and it is
easy to set the longer antenna element 2501 to a lower tuning
frequency and the shorter antenna element 2503 to a higher tuning
frequency, so that a desired antenna covering a broad band as a
whole can be implemented.
As shown in FIG. 54(b), a plurality of antenna elements may be
separately arranged in an antenna plane without winding round each
other.
If each of the antenna elements covers the same band, the
efficiency of the antenna can be improved.
To provide isolation between the antenna elements, a distance
between them may be determined to keep them in predetermined
isolation or an isolator or reflector may be connected to each of
the antenna elements.
It should be noted that the number of antenna elements is two or
three according to this example but it is not limited to this
example and may be any number equal to or more than two.
The antenna device of FIG. 55 differs from those in the preceding
examples in that as shown in FIG. 55(a), antenna elements 2601,
2602, and 2603 or antenna elements 2604, 2605, and 2606 are layered
in a direction perpendicular to the reference plane. It should be
noted that the antenna elements may be arranged so that they are
all exactly overlaid on the surface of projection as shown in the
left of the figure or so that they are partially overlaid as shown
in the right of the figure or so that they are separate from each
other. FIG. 55(b) is a partial broken view showing an application
of the present embodiment, in which antennas 2611 and 2612 are
formed on a multilayer printed circuit board 2609 through a
printed-wiring technique and the antennas are arranged to be
partially overlaid on the horizontal plane. Both elements can be
coupled in place by running a conductor through a through-hole
2610.
FIG. 56(a) shows an example of a single antenna feeding section for
serving a plurality of antenna elements. As shown in FIG. 56(a),
antenna elements 2701, 2702, and 2703 have taps 2704, 2705, and
2706 formed in place thereon, respectively, to connect them to a
feeding terminal 2707. It should be noted that the direction for
tapping is identical for all the antenna elements but it may be
arbitrarily determined for each of them.
FIG. 56(b) shows an antenna having a common electrode between the
tap of each antenna element and a feeding terminal. As shown in the
figure, taps 2704, 2705, and 2706 are formed in place on antenna
elements 2701, 2702, and 2703, respectively and a common electrode
2708 is provided between the taps and a feeding terminal 2707. This
makes the configuration very simple and in addition, more space can
be saved by placing the electrode 2708, for example, parallel to
the outermost antenna element 2701.
FIG. 57 shows an antenna with each antenna element tapped through a
reactance element. As shown in FIG. 57(a), antenna elements 2801,
2802, and 2803 may be separately connected to a feeding terminal
2807 through reactance elements 2804, 2805, and 2806, respectively,
or as shown in FIG. 57(b), a reactance element 2809 may be provided
within a common electrode 2808 between a feeding terminal 2807 and
taps. In the latter case, a reactance element may be provided
between the feeding terminal and a ground terminal. By using a
proper reactance element in this way, a desired impedance, band,
and maximum efficiency can be achieved. It should be noted that a
variable reactance element may be used as such a reactance element
for adjustment.
FIG. 58 shows that an antenna consists of a plurality of antenna
elements arranged in a predetermined range in the proximity of a
conductive earth substrate and served by a single feeding
mechanism, a ground terminal of which is connected to the
conductive earth substrate. As shown in FIG. 58, a plurality of
antenna elements 2901, 2902, and 2903 are served by a single
feeding terminal 2907 provided on the opposite side of a conductive
earth substrate 2909 to the antenna elements to provide an antenna
consisting of the group of antenna elements and a ground terminal
2908 of the feeding section is connected to the conductive earth
substrate 2909. This configuration can allow a compact high-gain
antenna to be provided in a plane in the proximity of the
conductive earth substrate.
In the antenna of FIG. 59(a), the tuning frequency is controlled by
setting a distance between opposed portions 3001 and 3002 of an
antenna element near its open terminals to a predetermined value to
control the coupling between them.
The coupling between the opposed portions 3001 and 3002 of the
antenna element near its open terminals can be established by
providing a dielectric 3003 as shown in FIG. 59(b) or by connecting
them through a reactance element 3004 as shown in FIG. 59(c). For
this purpose, the dielectric 3003 may be movably provided to
control the coupling or the reactance element 3004 may be
implemented with a variable reactance to control the coupling.
It should be noted that the number of antenna elements is one in
this example but it is not limited to this example and may be two
or more like the antenna shown in FIG. 54 described above.
In the antenna of FIG. 60(a), the tuning frequency is controlled by
setting a distance between open-terminal portions 3101 and 3102 of
an antenna element and the neutral point 3103 or their opposed
portions 3111 and 3112 near the neutral point to a predetermined
value.
The coupling between the open-terminal portions of the antenna
element and the neutral point or their opposed portions near the
neutral point can be established, as shown in FIGS. 60(b) and (c),
by providing a dielectric 3104 or by connecting them through a
reactance element 3105 or 3106. For this purpose, like the
thirteenth embodiment described above, the dielectric 3104 may be
movably provided to control the coupling or the reactance element
3101 or 3102 may be implemented with a variable reactance to
control the coupling.
It should be noted that the number of antenna elements is one also
in this example but it is not limited to this example and may be
two or more like the antenna shown in FIG. 54 described above.
In the antenna device of FIG. 61, at least one linear conductor is
connected to each end of a coil, a ground terminal is pulled out of
the neutral point of the coil, and a tap is formed in place on the
linear conductor or the coil to provide a feeding terminal at the
end of the tapping cable. As shown in FIG. 61(a), a coil 3203 has a
linear conductor 3201 or 3202 at each end of the coil, a ground
terminal 3206 is pulled out of the neutral point of the coil 3203,
and a tap 3204 is formed in place on the linear conductor (in this
case, 3202) to provide a feeding terminal 3205 at the end of the
tapping cable. As shown in FIG. 61(b), a tap 3204 may be formed in
place on a coil 3203 to provide a feeding terminal 3205.
This configuration can allow the tuning frequency of the antenna to
be adjusted by controlling the number of turns of coil winding and
in addition, it can allow the implementation of a more compact and
broadband antenna.
FIG. 62 shows that an antenna device has a plurality of linear
conductors connected to a coil. As shown in FIG. 62(a), a coil 3307
has a plurality of linear conductors 3301, 3302, and 3303 or 3304,
3305, and 3306 at each end of the coil, a ground terminal 3311 is
pulled out of the neutral point 3310 of the coil 3307, and a tap
3308 is formed in place on the linear conductors (in this case,
3304, 3305, and 3306) to provide a feeding terminal 3309 at the end
of the tapping cable. As shown in FIG. 62(b), a tap 3312 may be
formed in place on a coil 3307 to provide a feeding terminal 3309.
It should be noted that the three linear conductors are provided on
each side of the coil in this example but the number of conductors
is not limited to this example and may be any number equal to or
more than two.
It should be also noted that the conductors used as antenna
elements in this example are all linear but the shape of each
conductor is not limited to this example and any conductor may have
at least one bend or curve or may be spiral.
The antenna device of FIG. 63 has one or two groups of linear
conductors and each group of them is connected to a feeding section
through a coil. As shown in FIG. 63, a group of linear conductors
3401, 3402, and 3403 and another group of linear conductors 3404,
3405, and 3406 are connected to common electrodes 3407 and 3408,
respectively, and these electrodes are connected to a feeding
section 3411 through coils 3409 and 3410, respectively. This
configuration can allow the tuning frequency of the antenna to be
adjusted by controlling the number of turns of coil winding and in
addition, it can allow the implementation of a more compact and
broadband antenna.
The antenna device of FIG. 64 comprises a plurality of antennas
consisting of a plurality of antenna element groups and these
antennas are provided within a predetermined range for diversity
reception to select one of them which can achieve the optimum
receiving state. For example, in FIG. 64, two antennas 3501 and
3502 are switched by a diversity changeover switch 3503 connected
to a feeding section of each antenna to select one of the antennas
which can achieve the optimum radio-wave propagation. It should be
noted that the number of antennas is not limited to two as
described for this example but it may be three or more. It should
be also noted that the type of antennas is not limited to that
shown in FIG. 64 but other types of antennas as described for the
preceding embodiments, different types of antennas or the like may
be used.
In addition, controlling of selection of the optimum antenna from a
plurality of antennas may be accomplished by controlling selection
of one which can achieve the maximum receiver input or by
controlling selection of one which can achieve the minimum level of
multipath disturbance.
It should be further noted that a feeding section for serving each
antenna element or each antenna consisting of a plurality of
antenna element groups as described above may have a
balance-to-unbalance transformer, a mode converter, or an impedance
converter connected to it.
If each antenna described above is to be installed on an automobile
in a vertical position, for example, it may be installed on the end
3703 of an automobile spoiler 3701 or 3702, the end 3703 of a sun
visor or the like as shown in FIG. 65(a) or on a pillar section
3704 as shown in FIG. 65(b). Of course, installation locations are
not limited to those described here and the antenna may be
installed on any other locations which are tilted to some extent
with respect to any horizontal plane. Therefore, the reception of a
desired polarized wave can be made very easy by positioning the
antenna at such locations.
As described above, each antenna device described above can be
installed without any portion protruding from the body plane of an
automobile because it can be located with its antenna plane
parallel to and in the proximity of the body plane which is a
conductive earth substrate and in addition, it can be installed
even in a narrow space because it takes up only a small area.
Therefore, its appearance can be improved with little wind soughing
brought about around it and in addition, some other problems such
as a risk of its being stolen and labors involved in removing it
before car wash can be eliminated.
FIG. 66 is a schematic diagram showing an example of a mobile
communication device with an antenna device.
As shown in FIG. 66, an antenna 3801 according to any one of the
preceding embodiments described above is installed on the ceiling
of an automobile body 3805. In this case, if the antenna 3801 is
located within a recess 3806 in the ceiling, any portion of the
antenna will not protrude from the outline of the body 3805. The
antenna 3801 is connected to a communication device 3804 which is
installed inside the body 3805 and consists of an amplifier 3802, a
modem 3803 and the like.
FIG. 67(a) shows an example in which a conductive shielding case
3902 provided inside a resinous case 3901 of a portable telephone
is used as a conductive earth substrate and an antenna 3903 is
located along the inner side of the case 3901 to be parallel to the
shielding case 3902. FIG. 67(b) shows another example in which an
antenna 3904 is located on the top surface outside a resinous case
3901 of a portable telephone and a conductive earth substrate 3905
is provided on the inner wall of the case 3901 opposite to the
antenna 3904. In the latter case, the top of a shielding case 3902
is too small to be used as a conductive earth substrate. The
antennas used in FIGS. 67(a) and (b) are preferably those having
more bends or more turns of winding which can easily allow the
implementation of a compact antenna.
With these configurations, the directional gain on the conductive
earth substrate side is very small to the antenna and therefore,
possible influence of electromagnetic waves on human body can be
reduced without any degradation of antenna efficiency if the
antenna device is used with the conductive earth substrate side
turned to the user.
It should be noted that the antenna device is installed on an
automobile in the above description but it may be installed on
other vehicles such as an airplane or ship. Alternatively, it may
be installed not only on such vehicles but also on the roadbed,
shoulder, tollgate, or tunnel wall of any expressway such as
highway, or on the wall, window or the like of any building.
It should be also noted that the antenna device is used with a
mobile communication device in the above description but it may be
used with any other device which receives or transmits radio waves,
such as a television set, a radio-cassette player, or a radio set,
for example.
It should be further noted that the antenna device is implemented
in a portable telephone in the above description but it may apply
to other portable radio sets, such as a PHS (Personal Handy Phone
system) device, a pager, or a navigation system, for example.
FIG. 70(a) shows a monopole-type broadband antenna which comprises
a main antenna element 4202 having an end connected to a ground
4204, an antenna element 4201 located in the proximity of the main
antenna element 4202 and having a length longer than the antenna
element 4202 and no end connected to a ground, and an antenna
element 4203 having a length shorter than the antenna element 4202
and no end connected to a ground. The main antenna element 4202 is
provided with a tap which is connected to a feeding point 4206
through a reactance element 4205 for impedance adjustment. FIG.
70(b) shows another antenna device which is obtained by forming on
a printed circuit board 4207 antenna elements 4201, 4202, and 4203
of the antenna device of FIG. 70(a) described above through a
printed-wiring technique.
FIG. 71 shows a dipole-type antenna device of the configuration
described above. Namely, FIG. 71(a) shows a dipole-type broadband
antenna which comprises a main antenna element 4302 having the
center connected to a ground 4304, an antenna element 4301 located
in the proximity of the main antenna element 4302 and having a
length longer than the antenna element 4302 and no portion
connected to a ground, and an antenna element 4303 having a length
shorter than the antenna element 4302 and no portion connected to a
ground. The main antenna element 4302 is provided with a tap which
is connected to a feeding point 4306 through a reactance element
4305 for impedance adjustment. FIG. 71(b) shows another antenna
device which is obtained by forming on a printed circuit board 4307
antenna elements 4301, 4302, and 4303 of the antenna device of FIG.
71(a) described above through a printed-wiring technique.
These configurations can implement a broadband and high-gain
antenna device which is very simple and easy to adjust.
It should be noted that a shorter antenna element and a longer
antenna element are located in the proximity of a main antenna
element in this example but two or more antenna elements may be
located on each side of the main antenna.
FIG. 72(a) shows an antenna device similar to those shown in FIG.
40 or other figures described above, in which a conductive earth
substrate is located in the proximity of antenna elements and the
antenna device of this example differs from those devices in that a
conductive earth substrate 4404 located in the proximity of antenna
elements 4401, 4402, and 4403 is almost equal in size to or smaller
than the outermost antenna element 4401. Such a configuration can
improve the gain for horizontally polarized waves as compared with
the case where a conductive earth substrate is larger than an
antenna element.
FIG. 72(b) shows that the antenna device of FIG. 72(a) described
above is located within a recess in a vehicle body, the case of a
communication device, the wall of a house, any other device case,
or the like and that an antenna ground (conductive earth substrate)
4404 is not connected to a ground for such a case. This
configuration can provide a higher gain for both horizontally and
vertically polarized waves. The directional gain characteristics of
this antenna device are shown in FIG. 122 for vertically polarized
waves. As seen from the figure, when the distance (that is,
separation) between an antenna ground and a case ground is (a) 10
mm, (b) 30 mm, (c) 80 mm, or (d) 150 mm, the shorter distance can
provide the higher gain. Namely, when the antenna ground is closer
to the case ground, the better performance can be obtained. It
should be noted that in the example, the antenna ground 4404 is
located within a recess in a vehicle body, the case of a
communication device, the wall of a house, any other device case,
or the like to prevent the antenna from popping out of the outer
case but the antenna ground maybe located in the proximity of the
flat plane of the case ground at a distance, resulting in similar
effects. Even in the latter case, the antenna falls within the
scope of the present invention.
It should be also noted that an antenna element of balanced type is
used in this example but an antenna element of unbalanced type may
result in similar effects.
FIG. 73 shows how proximate to a conductive earth substrate an
antenna element is to be located and FIG. 73(a) is an example where
a single antenna element is located. Namely, the distance h between
an antenna element 4501 (to speak properly, an antenna grounding
connection) and a conductive earth substrate 4502 is set to a value
within 0.01 to 0.025 times as large as a wavelength .lambda. for
the resonance frequency f of the antenna (that is, 0.01.lambda. to
0.25.lambda.). This configuration can implement a high-gain antenna
which is very easy to adjust.
FIG. 73(b) is another example where four antenna elements 4503,
4504, 4505, and 4506 are located at different distances from a
conductive earth substrate 4507, respectively. As shown in FIG.
73(b), when the antenna elements have different lengths, the
shorter element can have the higher resonance frequency and the
shorter wavelength. Therefore, the distance h1 for the shortest
antenna element 4506 may be set to the smallest value, the distance
h2 for the longest antenna element 4503 may be set to the largest
value, and the distances for the medium antenna elements 4504 and
4505 may be set to values depending on the wavelengths at their
resonance frequencies, respectively. Then, the distance between
each of the antenna elements 4503, 4504, 4505, and 4506 and the
conductive earth substrate 4507 must satisfy the condition that it
falls within the range of 0.01 to 0.25 times as large as a
wavelength .lambda. for the resonance frequency f of each antenna
element (that is, 0.01.lambda. to 0.25.lambda.).
FIG. 74 shows that a high-permittivity material is provided between
an antenna element 4601 and a conductive earth substrate 4602.
Therefore, this configuration can apply to any other antenna device
described above where a conductive earth substrate is located in
the proximity of an antenna element. It should be also noted that
the distance between the antenna element and the conductive earth
substrate can be reduced equivalently by providing such a
high-permittivity material between them.
FIG. 75 shows that any one of the antenna devices described above
is installed at five locations in total, that is, one on each of
the four pillars 4701 and one on the roof, to provide a diversity
configuration of these flat antennas. This configuration can offer
a good capability of receiving and transmitting both horizontally
and vertically polarized waves. It should be noted that the antenna
device is installed at five locations in this example but it may be
installed at more or less locations.
FIG. 76 shows that any one of the antenna devices described above
is installed at any one or more locations on the roof panel, hood,
pillars, side faces, bumpers, wheels, floor, or other surface
portions of an automobile body 4801. In FIG. 76, an antenna 4802 is
installed at a location where the antenna plane is almost in a
horizontal position, an antenna 4803 is installed at a location
where the antenna plane is in a tilted position, and an antenna
4804 is installed at a location where the antenna plane is almost
in a vertical position. It should be noted that this figure shows
possible locations for antenna installation by way of example and
all the locations shown are not provided with antennas. Of course,
it should be also noted that an antenna may be installed at any
location other than those shown. It should be further noted that
the automobile type is not limited to such a passenger car as shown
and an antenna according to the present invention may be installed
on a bus, truck, or any other type of automobile.
In addition, since an antenna 4805 is installed at a location where
the antenna plane is in a horizontal position, and specifically, on
the back (undersurface) of the floor with its directivity facing
the roadbed, it is suitable for communication with a wave source
installed on the road (or embedded therein) which is to be used for
communication or detection of vehicle positions.
Generally, airwaves for TV or FM broadcasting mainly consist of
horizontally polarized waves, while waves for portable telephone,
radio communication, or the like mainly consist of vertically
polarized waves. Whether an antenna is suitable for horizontally
polarized waves or vertically polarized waves depends on the
direction of its installation. As shown in FIG. 77(a), an antenna
4902 which is installed parallel to a conductive earth substrate
4901, that is, a vertical surface portion of an automobile body
4801 and comprises three antenna elements of unbalanced type with
their grounded ends connected together is effective for
horizontally polarized waves, since its sensitivity to horizontally
polarized waves can be raised because of the horizontal electric
field as shown in the right of the figure. This can be accomplished
by installing an antenna 4804 as shown in FIG. 76. On the other
hand, an antenna 4802 which is installed parallel to a horizontal
surface portion of the automobile body 4801 is effective for
vertically polarized waves, since its sensitivity to vertically
polarized waves can be raised because of the vertical electric
field. In addition, an antenna 4803 which is installed in a tilted
position can be used regardless of the direction of polarization,
since its sensitivity is balanced between horizontally and
vertically polarized waves depending on the degree of tilt. FIG.
77(b) shows an example of antenna of balanced type, which is
effective for horizontally polarized waves in a similar manner to
that described above.
The antenna device of FIG. 78 differs from the antenna devices
described above in that it receives or transmits waves from the
side of its conductive earth substrate rather than from the side of
its antenna elements. As shown in FIG. 78(a), an antenna 5002 of
three antenna elements is installed parallel to a conductive earth
substrate 5001 at a distance and a grounded end of the antenna 5002
is connected to the conductive earth substrate 5001, which faces
toward the outside. This antenna has symmetrical directional
characteristics on the upper region of the conductive earth
substrate 5001 corresponding to the area covered by the antenna
5002 (on the opposite side to the antenna 5002 ) and on the lower
region there of as shown in FIG. 78(b). Therefore, even if the
antenna 5002 and the conductive earth substrate 5001 are located
inversely, it can achieve the same effect as those of the antennas
described above. In addition, even if a conductive earth substrate
5003 is formed as a sealed case as shown in FIG. 78(c), an antenna
5002 inside the conductive earth substrate 5003 can have similar
characteristics and communicate with the outside through the
conductive earth substrate 5003 when it is fed.
FIG. 79 shows an example of an antenna device of balanced type
which can achieve the same effect as those described above, while
FIG. 78 shows an antenna device of unbalanced type.
FIG. 80 is a schematic diagram showing possible locations where the
antenna device according to the present embodiment is to be
installed for automobile applications similar to those of FIG. 76.
In FIG. 80, like in FIG. 76, an antenna 5202 is installed at a
location where the antenna plane is almost in a horizontal
position, an antenna 5203 is installed at a location where the
antenna plane is in a tilted position, and an antenna 5204 is
installed at a location where the antenna plane is almost in a
vertical position. In addition, since an antenna 5205 is installed
at a location where the antenna plane is in a horizontal position,
and specifically, on the inner surface of the floor, it is suitable
for communication with a wave source installed on the road in a
similar manner to that of FIG. 76. Although these antennas shown
are all installed inside an automobile body 5201, they can achieve
the same performance as that for the antennas installed on the
outer surface of the automobile body for the reasons described
above and in addition, they are very advantageous in appearance,
damages, or risk of being stolen because they are not exposed to
the outside of the body. Moreover, as shown in FIG. 80, the antenna
device may be installed on a rearview mirror, in-car sun visor,
number plate, or any other location where it cannot be otherwise
installed on the outer surface, by embedding it within the inside
space of such a component.
FIG. 81 is a schematic diagram showing a possible application to a
portable telephone of any of the antenna devices described above,
in which an antenna 5302 is installed inside a conductive grounded
case 5301 with an antenna ground connected thereto. This
configuration can allow the antenna to be used in a similar manner
to the case where the antenna is installed outside the grounded
case 5301 and it can make the antenna very advantageous in handling
because the antenna is not exposed to the outside. It should be
noted that the antenna is used with a portable telephone in this
example but it can also apply to a TV, PHS, or other radio set.
FIG. 82 is a schematic diagram showing a possible application to an
ordinary house of any of the antenna devices described above.
Namely, an antenna 5402 is installed inside a conductive door of a
house 5401, an antenna 5403 is installed inside a conductive window
(for example, storm window), an antenna 5404 is installed inside a
conductive wall, and an antenna 5405 is installed inside a
conductive roof. Therefore, when an antenna is installed inside a
conductive structure of the house 5401 in this way, the antenna can
be protected against weather-induced damage or degradation with an
elongated service life because it is not exposed to the
outside.
It should be further noted that even if a house consists of
nonconductive structures, such an antenna can be installed at any
location by attaching a conductor to the outer surface thereof.
FIG. 83 shows that a conductive earth substrate 5501 and an antenna
5502 installed parallel to and in the proximity of the substrate
can be turned (or rotated) together on the axis as shown by a
dash-dot line. As shown in FIG. 83(a), when an antenna 5502 is in a
vertical position, the electric field is horizontal as shown in the
right of the figure and its sensitivity for horizontally polarized
waves becomes high. As shown in FIG. 83(b), when the antenna 5502
is in a horizontal position, the electric field is in turn vertical
as shown in the right of the figure and its sensitivity for
vertically polarized waves becomes high and therefore, the antenna
can be directed in the optimum position depending on the state of
polarized waves. Of course, it may be directed in a tilted
position. The directional gain characteristics of the antenna
installed as shown in FIG. 83(a) are shown in FIG. 123 and the
directional gain characteristics of the antenna installed as shown
in FIG. 83(b) are shown in FIG. 124. As apparent from these
figures, an antenna in a vertical position can exhibit a high
sensitivity to horizontally polarized waves, while an antenna in a
horizontal position can exhibit a high sensitivity to vertically
polarized waves.
It should be noted that the conductive earth substrate 5501 and the
antenna 5502 can be turned manually by operating the handle by hand
or automatically by using a motor or any other drive.
FIG. 84(a) is a schematic diagram showing the configuration of
another antenna device which can achieve the same effects as those
described above without turning the antenna. Namely, a
ferroelectric 5603 is located between a conductive earth substrate
5601 and an antenna 5602 so that it can sandwich the antenna 5602.
As shown in the right of FIG. 84(b), this configuration can allow
the electric field between a conductive earth substrate 5604 and an
antenna 5605 to be extended in a horizontal direction through a
ferroelectric 5606, so that the vertical component is decreased and
the horizontal component is increased as compared with the case
where no ferroelectric is used as shown in the left of the figure.
The antenna can be set for vertically polarized waves or
horizontally polarized waves depending on whether a ferroelectric
is used or not. It should be noted that if the antenna is installed
in a vertical position, such a ferroelectric will have an inverse
effect on the antenna. It should be further noted that the
ferroelectric 5603 may be installed during the manufacture or not
and it may be made easily removable by providing grooves for this
purpose.
Although the antenna devices described above use bent elements
which can be installed even in a narrow space, each of the antenna
devices of FIG. 85 uses a linear element which can be installed on
an elongate component of an automobile or an element shaped to a
component.
FIG. 85(a) shows that a linear antenna 5702 with three elements is
located in the proximity of the surface of an elongate platelike
conductive earth substrate 5701. FIG. 85(b) shows that a linear
antenna 5704 with three elements is located in the proximity of the
surface of a cylindrical conductive earth substrate 5703 so that
each element is at the same distance from the conductive earth
substrate 5703. FIG. 85(c) shows that a linear antenna 5706 with
three elements is located in the proximity of the surface of a
quadrangular-prism conductive earth substrate 5705 so that each
element is at the same distance from the conductive earth substrate
5705.
FIG. 86 shows variations of the antennas shown in FIG. 85, in which
elements are curved or bent in accordance with a curved or bent
conductive earth substrate. FIG. 86(a) shows that an antenna 5802
with three curved elements is located in the proximity of the
surface of a curved cylindrical conductive earth substrate 5801 so
that each element is at the same distance from the conductive earth
substrate 5801. FIG. 86(b) shows that an antenna 5804 with three
bent elements is located in the proximity of the surface of a bent
quadrangular-prism conductive earth substrate 5803 so that each
element is at the same distance from the conductive earth substrate
5803. FIG. 86(c) shows that an antenna 5806 with three bent
elements is located in the proximity of the surface of a bent
platelike conductive earth substrate 5805.
In addition, FIG. 87(a) shows that an antenna 5902 is located along
the surface of a cylindrical conductive earth substrate 5901 and
FIG. 87(b) shows that an antenna 5904 is located along the surface
of a spherical conductive earth substrate 5903.
It should be noted that the antenna in this example is located
outside a component which constitutes a conductive earth substrate
but it is not limited to this example and it may be located inside
a platelike component or on the inner surface of a cylindrical
component.
FIGS. 91 and 93 show applications of the antenna device according
to the present embodiment. FIG. 91 shows that an antenna 6302 is
installed on the surface of an elongate roof rail 6303 on the roof
of an automobile body 6301 and FIG. 93 shows that an antenna 6502
is installed inside an elongate roof rail 6503 on the roof of an
automobile body 6501.
Moreover, FIGS. 92 and 94 show other applications of the antenna
device according to the present embodiment. FIG. 92 shows that an
antenna 6403 is installed on the surface of an elongate roof box
6402 on the roof of an automobile body 6401 and FIG. 94 shows that
an antenna 6603 is installed inside an elongate roof box 6602 on
the roof of an automobile body 6601.
The antenna device shown in FIGS. 88(a) and 88(b) comprises an
antenna 6002 with three longer elements and an antenna 6003 with
three shorter elements with respect to a grounded point connected
to a conductive earth substrate 6001 and feeding points A 6005 and
B 6004 are provided for these antennas 6002 and 6003, respectively.
As shown in FIG. 88(c), the shorter antenna 6003 is tuned to the A
band of relatively higher frequencies and the longer antenna 6002
is tuned to the B band of relatively lower frequencies, and thus,
such a single antenna device can accommodate two tuning bands. It
should be noted that the feeding points A 6005 and B 6004 may be
connected to each other.
FIGS. 89(a) and 89(b) show another example of the antenna of
unbalanced type having two tuning bands. This antenna is a
four-element antenna having an end connected to a conductive earth
substrate 6101 and located in the proximity of the conductive earth
substrate 6101 and in addition, an antenna 6102 with two relatively
longer elements is provided with a feeding point B 6104 and an
antenna 6103 with two relatively shorter elements is provided with
a feeding point A 6105. As shown in FIG. 8[sic] (c), this
configuration can accommodate two tuning bands, that is, the A band
of relatively higher frequencies and the B band of relatively lower
frequencies in a similar manner to that of the preceding example.
It should be also noted that the feeding points A 6005 and B 6004
may be connected to each other.
FIGS. 90(a) and 90(b) show still another example of the antenna of
balanced type having two tuning bands. This antenna is a
four-element antenna having the midpoint connected to a conductive
earth substrate 6201 and located in the proximity of the conductive
earth substrate 6201 and in addition, an antenna 6202 with two
relatively longer elements is provided with a feeding point B 6204
and an antenna 6203 with two relatively shorter elements is
provided with a feeding point A 6205. As shown in FIG. 90(c), this
configuration can accommodate two tuning bands, that is, the A band
of relatively higher frequencies and the B band of relatively lower
frequencies in a similar manner to that of the preceding examples.
It should be also noted that the feeding points A 6005 and B 6004
may be connected to each other.
Like this, the antenna described above can provide an advanced
antenna device which requires a minimum space for installation and
which is capable of accommodating a plurality of tuning bands, and
thus, such an antenna can be applicable in a narrow space such as
an automobile or a portable telephone.
It should be noted that this example assumes two tuning bands but
it may accommodate three or more bands. The latter case can be
accomplished by providing a plurality of antennas each of which has
an element length corresponding to each tuning band and providing a
feeding point for each antenna.
In the antenna device of FIG. 95, a coil 6703 is provided in place
on a three-edge antenna element 6701 located in the proximity of a
conductive earth substrate 6702 and an end of the antenna element
6701 is connected to the conductive earth substrate 6702. In
addition, a feeding section 6704 is provided on the antenna element
6701 between the coil 6703 and the conductive earth substrate 6702.
This configuration can allow an electric current to concentrate in
the coil and thus the antenna device can be reduced in size with
the gain unchanged. For example, if the antenna element consists of
a strip line, the area for the antenna can be reduced to a quarter.
Moreover, its bandwidth can be narrowed with a sharp band
characteristic.
FIG. 96 shows that two antenna elements having the configuration of
FIG. 95 are connected in parallel for band synthesis. Namely, two
antenna elements 6801 a and 6801b having different bands (lengths)
and coils 6803 a and 6803b provided in place on the elements,
respectively, are located in parallel and an end of each element is
connected to a conductive earth substrate 6802. In addition, the
antenna elements 6801a and 6801b are connected to a common feeding
section 6804 through reactance elements 6805a and 6805b,
respectively. This configuration can synthesize the bands of the
two antenna elements and thus, a broadband antenna device with the
same effects as those described above can be implemented.
In the antenna device of FIG. 97, a coil 6903 is provided between
an end of a three-edge antenna element 6901 located in the
proximity of a conductive earth substrate 6902 and the conductive
earth substrate 6902 and the other end of the coil 6903 is
connected to the conductive earth substrate 6902 for grounding. In
addition, a feeding section 6904 is provided in place on the
antenna element 6901. This configuration can allow an electric
current to concentrate in the coil in a similar manner to that for
the thirty-second embodiment described above and thus the antenna
device can be reduced in size with the gain unchanged.
FIG. 98 shows that two antenna elements having the configuration of
FIG. 97 are connected in parallel for band synthesis. Namely, two
antenna elements 7001a and 7001b having different bands (lengths)
are located in parallel with an end connected to an end of a common
coil 7003 and the other end of the coil 7003 is connected to a
conductive earth substrate 7002. In addition, the antenna elements
7001a and 7001b are connected to a common feeding section 7004
through reactance elements 7005a and 7005b, respectively. This
configuration can synthesize the bands of the two antenna elements
and thus, a broadband antenna device with the same effects as those
described above can be implemented. It should be noted that the
single coil which is shared by the two antenna elements can
contribute to a simple configuration.
The antenna of FIG. 99 differs from that of FIG. 97 described above
in that as shown in FIG. 99, an insulator 7105 is provided on a
conductive earth substrate 7102 and an antenna element 7101 and a
coil 7103 are connected on the insulator 7105. This configuration
can allow easy installation of a coil 7103, which is useful for its
implementation, and thus the coil can be stably installed. FIG. 100
shows the configuration of two antenna elements 7201a and 7201b
arranged for band synthesis. As shown in the figure, although the
connection between a coil 7203 and the antenna elements becomes
more complex because of the more antenna elements as compared with
the preceding case, a connection point provided on an insulator
7205 on a conductive earth substrate 7202 can make the connection
between the antenna elements and the coil much easier.
In the antenna device of FIG. 101, two coil sections are separately
provided and two insulators 7305a and 7305b are provided on a
conductive earth substrate 7302 to connect antenna elements and
coils. Namely, an end of a three-edge antenna element 7301 provided
in the proximity of a conductive earth substrate 7302 and an end of
a coil 7303a are connected together on an insulator 7305a, the
other end of the coil 7303a and an end of another coil 7303b and a
feeding section 7304 are connected together on another insulator
7305a, and the other end of the coil 7303b is connected to the
conductive earth substrate 7302 for grounding. FIG. 102 shows an
antenna device having two antenna elements 7401a and 7401b arranged
for band synthesis and the antenna elements, coils, and a feeding
section are connected in a similar manner to that shown in FIG.
101.
These configurations can allow easy connection to other circuit
components because the feeding terminal is provided on a circuit
board.
In the antenna device of FIG. 103, a zigzag pattern 7503 is
inserted in an antenna element 7501 in place of the coil for the
configuration of FIG. 95. Although the configuration having a coil
can three-dimensionally extend, the configuration with this pattern
7503 can be formed on the same plane as the antenna element 7501
and fabricated through a printed-wiring technique. FIG. 104 shows
an antenna device having two antenna elements 7601a and 7601b
arranged for band synthesis and zigzag patterns 7603a and 7603b are
inserted in antenna elements 7601a and 7601b, respectively. It
should be noted that the zigzag patterns may be sawtoothed ones as
shown in FIG. 106(c).
In the antenna device of FIG. 105, the whole antenna element 7701
located in the proximity of a conductive earth substrate 7702 is
formed in a zigzag pattern and an end of the antenna element 7701
is connected to an end of a coil 7703 which is grounded at the
other end. In addition, a feeding section 7704 is provided in place
on the zigzag antenna element. This configuration can allow the
antenna device to be further reduced in size, for example, to 1/6
or 1/8, although possible losses may be increased. It should be
noted that the antenna element may be formed in other patterns, for
example, those shown in FIGS. 106(b) and (c). The pattern shown in
FIG. 106(b) is a three-dimensional coil.
In the antenna device of FIG. 107, an insulator 7904 is provided on
a conductive earth substrate 7902 and a lead 7905 from an antenna
element 7901 and a feeding section 7903 are connected together on
the insulator 7904. This configuration can allow easy connection
with other circuit components because the feeding section 7903 is
provided on a circuit board.
FIG. 108 shows that a through-hole 8005 is formed in a conductive
earth substrate 8002 to provide an insulator 8004 on the opposite
side of the conductive earth substrate 8002 to an antenna element
8001. A lead 8006 from the antenna element 8001 passes through the
through-hole 8005 and the insulator 8004 and connects to a feeding
section 8003 on the insulator 8004. This configuration can make it
much easier than that of FIG. 107 described above to connect other
circuit components to the feeding section 8003 because such circuit
components can be connected on the back of the 8002.
FIG. 109 shows that in addition to the configuration of FIG. 108
described above, another conductive plate is provided on the back
of a conductive earth substrate (on the opposite side to an antenna
element) to mount various circuit components thereon. Namely, a
through-hole 8104 is formed in both a conductive earth substrate
8102 and a conductive plate 8105 to run a lead 8111 from an antenna
element 8101 therethrough and an insulator 8103 is provided on the
conductive plate 8105 over the through-hole 8104. In addition, a
required number of insulators 8106 are provided on the conductive
plate 8105 to connect various circuit components. The lead 8111
passes through the through-hole 8104 to the insulator 8103 and
circuit components 8107 to 8110 are connected on the insulators
8103 and 8106.
This configuration can allow location of the circuit in the
proximity of the antenna and easy shielding between the antenna and
the circuit through the conductive plate, and thus, it can
facilitate implementing a compact device.
FIG. 110 shows still another example of the antenna in which
circuit components are located on the same side as an antenna
element. Namely, an insulator 8203 to connect a lead 8205 from an
antenna element 8201 and a required number of insulators 8206 to
connect various circuit components are provided on a conductive
earth substrate 8202. In addition, a conductive shielding case 8204
is provided on the conductive earth substrate 8202 to shield the
circuit components on the conductive earth substrate 8202 from the
antenna element 8201 and a through-hole 8207 is formed for running
the lead 8205 therethrough. The lead 8205 passes through the
through-hole 8207 to connect to the insulator 8203 and circuit
components 8208 to 8210 are connected on the insulators 8203 and
8206. An end of the antenna element 8201 is connected to the
shielding case 8204 for grounding.
This configuration can allow the whole circuit to be held between
the antenna element and the conductive earth substrate and to be
shielded by the shielding case, and thus, it can facilitate
implementing a more compact device than the configuration of FIG.
109 described above.
In the antenna device of FIG. 111, an antenna element 8301 is
formed on one side of an insulation plate 8305 and one end 8307 of
the antenna element 8301 passes through the insulation plate 8305.
A lead 8303 from a point in the antenna element 8301 also passes
through the insulation plate 8305 and another lead 8306 formed on
the opposite side of the insulation plate 8305 and parallel to the
antenna element 8305[sic] is connected to the lead 8303 for
connecting a feeding section 8304 to the lead 8306. It should be
noted that the feeding section 8304 is provided in the proximity of
the end 8307 of the antenna element 8301. In addition, the
insulation plate 8305 is located parallel to a conductive earth
substrate 8302, to which the end 8307 of the antenna element 8301
is connected.
This configuration can facilitate connecting coaxial cables because
the grounded end of the antenna element is close to the feeding
section.
In the antenna device of FIG. 112, a conductive earth substrate
8404 is provided on another broader conductive earth substrate 8402
through an insulation plate 8405 and an antenna element 8401 is
located in the proximity of the conductive earth substrate 8404. It
should be noted that an end of the antenna element 8401 is
connected to the conductive earth substrate 8404 for grounding. It
should be preferable that the conductive earth substrate 8404 is
equal to the antenna element 8401 in size. Specifically, the
conductive earth substrate 8402 may be the body of an automobile or
carriage, the metal case for a receiver or communication device, or
any metal structure of a house and it may be installed inside or
outside the room or compartment.
This configuration can achieve a nearly horizontal elevation angle
with the maximum gain and thus, it will be suitable for receiving
communication waves (vertically polarized waves) which come from a
lateral direction.
It should be noted that any of the antenna devices shown in FIGS.
95 through 112 can be installed at such locations as shown in FIGS.
65, 75, 76, 80, 81, and 82 to operate properly.
It should be also noted that one or two antenna elements are used
in any of the antenna devices shown in FIGS. 95 through 112 but of
course, three or more antenna elements may be used.
It should be further noted that antenna elements used in any of the
antenna devices shown in FIGS. 95 through 112 are in a three-edge
shape but they may be in a loop or any other shape.
It should be further noted that insulators used to provide
connection points in any of the antenna devices shown in FIGS. 107
through 112 may apply to any other antenna devices according to the
preceding embodiments described above.
Next, other embodiments of the present invention which are devised
mainly to improve the gain will be described below.
FIG. 126 is a perspective view showing an embodiment according to
the present invention.
In the figure, the reference numeral 4003 designates a conductive
earth substrate, to which a main element 4001 is connected through
a first ground connection 4005 so that it is substantially parallel
to the substrate. The connection between the main element 4001 and
the first ground connection 4005 is connected to another ground
4007. In addition, a feeding terminal 4006 is connected to a point
in the main element 4001 and a grounding terminal of the feeding
terminal 4006 is connected to the ground 4007.
A passive element 4002 is also connected to the conductive earth
substrate 4003 through a second ground connection 4004 along the
main element 4001.
As seen from the graphs shown in FIGS. 139 and 149[sic], the gain
can be improved by providing such a passive element 4002 in this
way. In the figure, the line with white squares indicates an ideal
monopole antenna, the line with black squares indicates a
one-element antenna, and the line with black circles indicates an
embodiment according to the present invention. It can be seen from
the figure that the gain characteristics are improved for a
specific narrow-band.
FIG. 127 shows another embodiment according to the present
invention, which differs from the embodiment of FIG. 126 in that a
feeding terminal 4006 is grounded with a conductive earth substrate
4003. It should be noted that the embodiment of FIG. 126 can
achieve a better gain than this embodiment.
FIG. 128 shows still another embodiment according to the present
invention and a main element 4001 and a passive element 4002 are
both formed in a circular shape in this embodiment, while they are
formed in a straight shape in the embodiment of FIG. 126. It should
be noted that the passive element 4002 may be located inside or
outside the main element 4001.
FIG. 129 shows various types of the main element 4001 and the
passive element 4002 as plan views taken in a direction
perpendicular to the conductive earth substrate 4003. Specifically,
FIG. 129(a) shows a straight type, FIGS. 129(b) through (d) show
bent types, and FIGS. 129(e) and (f) show circular types. In
addition, the reference numeral 4010 designates the directivity of
each type. As seen from the figures, such an approximately circular
type as shown in FIG. 129(f) can achieve the best omnidirection.
Conversely, if a specific directivity is desired, another type of
elements which can achieve that directivity may be selected.
FIG. 130 shows a circular type, in which a feeding terminal 4006 is
grounded with a conductive earth substrate 4003.
FIG. 131 shows another circular type, in which a feeding terminal
4006 is grounded with a specifically provided ground 4007 rather
than a conductive earth substrate 4003.
FIG. 132 shows another embodiment according to the present
invention, in which a larger ground 4012 such as an automobile body
is provided under a conductive earth substrate 4003 through an
insulator 406011[sic]. It should be preferable that the size and
shape of the insulator 4011 are equal to those of the outer main
element 4001. If a passive element 4002 is provided as the outer
element, it should be preferable that the size and shape of the
passive element 4002 are equal to those of the insulator 4011. It
should be also preferable that the distance between the main
element 4001 and the passive element 4002 is approximately
1/600.lambda., the distance between both elements 4001 and 4002 and
the conductive earth substrate 4003 is approximately 1/20.lambda.,
and the thickness of the insulator 4011 is approximately
1/60.lambda.. FIG. 133 shows that the ground connections 4004 and
4005 in FIG. 128 can be formed as a single connection plate 4013.
This configuration can provide a simpler antenna device for a
narrower band.
FIG. 134 shows that two passive elements 4002, 4002[sic] are
provided, one on each side of a main element 4001. This
configuration can provide two gain peaks as shown in FIG.
134(b).
FIG. 135 shows that two circular main elements 4001 are provided in
parallel and a common feeding terminal 4006 is connected to them
through a capacitor 4014. This configuration can accomplish band
synthesis. FIG. 135(b) shows the result of such band synthesis.
FIG. 136 shows that two passive elements 4003[sic], 4003 are
provided, one on each side of the two main elements 4001 shown in
FIG. 135. This configuration can provide such an improved band
synthesis gain as shown in FIG. 136(b) as compared with the example
of FIG. 135.
FIG. 137 shows that a passive element 4003 is provided between the
two main elements 4001, 4001[sic] shown in FIG. 135.
FIG. 138 shows that a circular main element 4001 is provided on the
top surface of a printed circuit board 4015 and a passive element
4002 is provided on the undersurface of the printed circuit board
4015. The main element 4001 and the passive element 4002 are
located in opposed positions with respect to each other. A
conductive earth substrate 4003 as described above is provided
parallel to the printed circuit board 4015.
Next, several embodiments of a digital television broadcasting
receiving device, in which any of the above-mentioned antenna
devices according to the present invention is used, will be
described below.
(Embodiment 10)
FIG. 138[sic] is a block diagram showing the configuration of a
digital television broadcasting receiving device according to the
embodiment 10 of the present invention. In FIG. 138[sic], the
reference numeral 6001 designates an input means, 6002 designates a
delay means, 6003 designates a synthesis means, 6004 designates a
reception means, 6005 designates a demodulation means, 6007
designates a delayed wave estimation means, 6008 designates a
positional information determination means, and 6009 designates a
vehicle information detection means. The operation for receiving
digital television broadcasting at a vehicle will be described
below with reference to FIG. 141.
A television broadcasting wave is converted to an electric signal
by the input means 6001 such as a receiving antenna and then
supplied to the delay means 6002 and the synthesis means 6003. The
television broadcasting wave converted to such an electric signal
is delayed by the delay means 6002 in accordance with a delay
control signal from a synthesis control means 6006 and then
supplied to the synthesis means 6003. In the synthesis means 6003,
in accordance with a synthesis control signal from the synthesis
control means 6006, a signal from the input means 6001 and another
signal from the delay means 6002 are provided with a predetermined
gain for each signal and synthesized together and then supplied to
the reception means 6004. As a synthesis technique used for this
purpose, addition, maximum selection, or other simple operations
can be used.
The reception means 6004 extracts only signals within a necessary
band from those supplied by the synthesis means 6003 and converts
them to signals of frequencies which can be handled by the
demodulation means 6005. Thus converted signals are supplied to the
demodulation means 6005, which in turn demodulates them for output.
The demodulation means 6005 supplies demodulation information to
the delayed wave estimation means 6007, which estimates a delayed
wave contained in the received wave based on the demodulation
information supplied by the demodulation means 6005.
The operations for demodulation and delayed wave estimation will be
described below. In the ground wave digital broadcasting which is
now being standardized in Japan, orthogonal frequency-division
multiplexing (OFDM) is used for modulation and the demodulation
means 6005 performs OFDM demodulation to decode transmitted codes.
During the decoding process, frequency analysis is performed
through an operation such as FFT. The transmission characteristics
of a received signal can be estimated by using various pilot
signals contained in the received signal for data demodulation. For
example, a delay time can be detected by detecting dip locations
and the number of dips in frequency components which are obtained
from the FFT frequency analysis.
FIG. 147 shows an example of the frequency analysis performed for
OFDM and the frequency characteristics may be flat when no delayed
wave exists, while the frequency components may have some dips as
shown in FIG. 147 when some delayed waves exist. Alternatively, a
delayed wave can be detected by observing any variation in or lack
of pilot signals. The delay time of a disturbance wave can be
estimated based on erroneous data positional information obtained
through an error correction process performed after the FFT
operation. It should be noted that the Japanese digital
broadcasting has been described in the above paragraphs but this
technique may apply also to analog broadcasting or foreign digital
broadcasting.
Next, the operations for synthesis control and delay control will
be described below. The synthesis control means 6006 provides a
signal to control the delay means 6002 and the synthesis means 6003
based on estimated delayed wave information supplied by the delayed
wave estimation means 6007. The configuration of the synthesis
control means 6006 which comprises a gain control means 6061 and a
delay time control means 6062 will be described below. The gain
control means 6061 establishes a synthesis gain in the synthesis
means 6003 based on delayed wave information supplied by the
delayed wave estimation means 6007. This establishing operation
will be described below with reference to FIG. 148. In FIG. 148,
the axis of abscissas shows the magnitude of a delayed wave and the
axis of ordinates shows a ratio of the gain of a signal supplied by
the input means 6001 (signal A gain) to the gain of a signal
supplied by the delay means 6002 (signal B gain) (=signal A
gain/signal B gain). The synthesis gain is controlled so that both
gains can be identical when the level of a delayed wave is large
and in particular, it is equal to the level of a direct wave or so
that a difference between both gains can be obtained by decreasing
the gain of a signal supplied by the delay means or that of a
signal supplied by the input means when the level of a delayed wave
is small or, when the level of a delayed wave is larger than that
of a direct wave. In addition, if the gain control is accomplished
based on the delay time of a delayed wave supplied by the delayed
wave estimation means 6007, the gain difference becomes larger for
the case of a large delay time (the curve a in FIG. 148) than the
case of a small delay time (the curve b in FIG. 148).
Next, the operation of the delay time control means 6062 will be
described below. It controls the establishment of a delay time to
be used by the delay means 6002 so that the delay means 6002 delays
the time by a length almost equal to the delay time estimated by
the delayed wave estimation means 6007. For example, the
relationship between error rates of a delayed wave and a
demodulated signal is shown in FIG. 149. As shown in the figure,
because the error rate may deteriorate abruptly when a delay time
is small (point B: approximately 2.5 .mu.s or less), such a
deterioration in error rate can be effectively avoided by using a
fixed delay time, for example, a delay time exceeding the point B
in FIG. 149, rather than a delay time estimated by the delayed wave
estimation means 6007 when the estimated delay time is small. It
should be noted that such a delay time to be established here must
be at most shorter than a guard period added to an OFDM signal. In
order to prevent such a deterioration in error rate from occurring
due to the small delay time of a delayed wave, the delay means 6002
can always establish a predetermined delay time. For this purpose,
any influence of a short delay time can be eliminated by setting
such a delay time to a value nearly twice as large as the point B.
If a signal is received by a single antenna as shown in FIG. 141, a
delay time smaller than the reciprocal of the bandwidth of a
received signal can be added to the signal to decrease the noise
level of the received signal with an improved error rate. This is
because dips caused by the added signal will appear outside the
signal bandwidth. For example, if the signal bandwidth is 500 kHz,
an added delay time must be established to be 2 .mu.s or less. The
operation for adding a signal with a short delay time as described
above can be effective in improving the reception level of signal
bandwidth for narrowband broadcasting which is used as broadcasting
services for mobile reception.
Next, the usage of the vehicle information detection means 6009
will be described below. The vehicle information detection means
6009 detects information on a moving reception vehicle. For
example, this means may consist of a speed (vehicle speed)
detection means 6091 which detects the speed of a moving reception
vehicle and a position detection means 6092 which detects the
position of such a vehicle. It goes without saying that the vehicle
information detection means 6009 can be implemented by a navigation
system and that the position detection means can be implemented by
using a GPS system or by detecting locations through a PHS, a
portable telephone set, or a traffic control system such as VICS.
Detected vehicle information is supplied to the positional
information determination means 6008.
The positional information determination means 6008 checks which
broadcast station covers the current location and estimates the
delay time and the strength of a wave received at the receiving
location, taking account of the distance from such a station as
well as possible reflections from mountains and buildings. To this
end, this means has previously obtained information including the
transmission frequency and location or transmission power of each
transmitting station such as a broadcast station or relay station
or downloaded it through any communication means such as
broadcasting or telephone into its storage to compare it with the
positional information supplied by the vehicle information
detection means 6009. From this information, the delay time and
magnitude of a wave received at that receiving location can be
estimated.
Moreover, the delay time and magnitude of a received wave can be
obtained more accurately, by marking in a map information including
the location, magnitude, and height of each building located near
the receiving location in addition to the location of each
broadcasting station and taking account of possible reflections
therefrom. It goes without saying that a navigation system can be
used to handle such information on the transmitting stations,
buildings, and mountains. It should be also noted that a delayed
wave can be tracked more quickly because the following delayed wave
can be estimated by knowing the speed of a moving reception vehicle
through the speed detection means 6091.
The synthesis control means 6006 controls the synthesis gain and
the delay time based on the delayed wave information supplied by
the positional information determination means 6008 as described
above. These control operations can be performed in a similar
manner to those based on the delayed wave information supplied by
the delayed wave estimation means 6007. In addition, the
information from the delayed wave estimation means 6007 can be used
in combination with that from the positional information
determination means 6008 and then the gain and delay time may be
controlled only if these two kinds of delay information are similar
to each other or they may be controlled to remain unchanged or they
may be controlled in accordance with the information containing a
larger level of delayed wave if these two kinds of delay
information are quite different from each other. It should be noted
that in the description above, the vehicle information detection
means 6009 is provided for mobile reception but both mobile and
stationary reception can be accomplished by using the position
detection means 6092 only.
The configuration described above has only one input means as shown
in FIG. 141 but another configuration shown in FIG. 142 which has a
plurality of input means and a plurality of delay means
corresponding to the input means, respectively, is also effective
for mobile reception. Each input means of this configuration is
provided with a different input signal because it is affected by a
different level of multipath interference even when it receives the
same broadcasting wave. This may cause dips at different locations
(frequencies) and different depths as shown in FIG. 147. Therefore,
a plurality of different input signals can be added together to
provide another dip at a different location and depth, resulting in
a lower signal error rate. The reception operation of the device
shown in FIG. 142 is almost identical to that described for FIG.
141. Under the control of the delay means 6002 and the synthesis
means 6003, a desired delay time is established with the delay
means 1 through N in a relative manner and the gain can be set in
accordance with the delayed signal. If the distance between a
plurality of antenna locations is sufficiently shorter than the
wavelength of the baseband, the level of received signals can be
improved by adding a plurality of input signals within the
baseband.
As described above, the digital television broadcasting receiving
device according to the embodiment 10 can reduce signal dips
through synthesis of signals, resulting in an improved error rate
of digital data. Any deterioration in error rate can be avoided by
establishing a delay time to prevent any influence of a signal with
a shorter delay time. In addition, signal dips can be avoided more
accurately by producing an accurate delayed wave through the
delayed wave estimation means, the vehicle information detection
means, and the positional information determination means and thus,
the error rate can be further improved.
Signals received through a plurality of antennas can be switched
depending on their error conditions. The antenna switching
conditions for changing over from one antenna to another will be
described below with reference to FIG. 150. First, the C/N ratio of
an input signal and the length of a past period such as a frame
period thereof are determined and antenna switching is not
performed if the C/N ratio is large and the error rate is low. If
an error is a burst one of very short period and does not continue
for a while even when the error rate is high, antenna switching is
not performed. If the C/N level of an input signal is lowered or if
a high error rate continues for a while, antenna switching is
performed. The timing for antenna switching may be set to a guard
interval appended to an OFDM signal. Alternatively, such an antenna
switching timing may be calculated from a combination of vehicle
speed information and positional information. It should be noted
that the timing for antenna switching may be set to a guard
interval appended to an OFDM signal. This can allow optimum antenna
switching in accordance with varying reception conditions during
the mobile reception. It should be also noted that by providing an
antenna 6011 and an amplification means 6012 as components of the
input means shown in FIGS. 141 and 142, any signal attenuation or
matching loss due to distribution can be avoided to perform the
succeeding operation accurately.
(Embodiment 11)
FIG. 143 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to the
embodiment 11[sic] of the present invention. In FIG. 143, the
reference numeral 6001 designates an input means, 6002 designates a
delay means, 6003 designates a synthesis means, 6004 designates a
reception means, 6005 designates a demodulation means, 6007
designates a delayed wave estimation means, 6008 designates a
positional information determination means, and 6009 designates a
vehicle information detection means. The configuration of the
embodiment 11 as shown in FIG. 143 differs from that of the
embodiment 10 described above in that the reception means 6004 is
connected directly to the input means 6001. The operation for
receiving digital television broadcasting at a vehicle according to
the embodiment 11 will be described below.
A television broadcasting wave is converted to an electric signal
by the input means 6001 such as a receiving antenna and then
supplied to the reception means 6004. The reception means 6004
extracts only signals within a necessary band from those supplied
by the input means 6001 and supplies them to the delay means 6002
and the synthesis means 6003. Those signals supplied by the
reception means 6004 are delayed by the delay means 6002 in
accordance with a delay control signal from a synthesis control
means 6006 and then supplied to the synthesis means 6003. In the
synthesis means 6003, in accordance with a synthesis control signal
from the synthesis control means 6006, a signal from the reception
means 6004 and another signal from the delay means 6002 are
weighted with a predetermined gain added to each signal and
synthesized together and then supplied to the demodulation means
6005. As a synthesis technique used for this purpose, addition,
maximum selection, or other simple operations can be used in a
similar manner to that for the embodiment 10 described above. The
demodulation means 6005 demodulates them for output.
In a similar manner to that for the embodiment 10, a delayed wave
is estimated in the delayed wave estimation means 6007 and the
positional information determination means 6008 from demodulation
information supplied by the demodulation means 6005 and mobile
reception information supplied by the vehicle information detection
means 6009, respectively, and then supplied to the synthesis
control means 6006, which in turn controls the delay and synthesis
operations by producing control signals to be supplied to the delay
means 6002 and the synthesis means 6003. The detailed operations of
the synthesis control means and the vehicle information detection
means performed during the reception operation described above are
identical to those for the embodiment 10. In the receiving device
according to the embodiment 11, the operations of the delay means
6002 and the synthesis means 6003 can be simplified because the
frequencies and bands are limited by the reception means 1, but the
same effects as those of the embodiment 10 can be achieved.
As shown in FIG. 144, a plurality of input means 6001, a plurality
of reception means 6004, and a plurality of delay means 6002 can be
provided for reception. The operation of this configuration shown
in FIG. 144 is identical to that for the preceding embodiment
described above and will not be described here in detail. Because a
plurality of input means 6001, a plurality of reception means 6004,
and a plurality of delay means 6002 are provided, each input means
of this configuration is provided with a different input level due
to a different condition of interference even when it receives the
same broadcasting wave. This may cause dips at different locations
(frequencies) and different depths as shown in FIG. 147. Therefore,
a plurality of different input signals can be added together to
provide another dip at a different location and depth, resulting in
a lower signal error rate.
(Embodiment 12)
FIG. 145 is a block diagram showing the configuration of a digital
television broadcasting receiving device according to the
embodiment 12[sic] of the present invention. In FIG. 145, the
reference numeral 6001 designates an input means, 6004 designates a
reception means, 6005 designates a demodulation means, 6007
designates a delayed wave estimation means, 6055 designates a
demodulation control means, 8[sic] designates a positional
information determination means, and 9[sic] designates a vehicle
information detection means. The operation for receiving digital
television broadcasting at a moving vehicle or a fixed location
will be described below with reference to FIG. 145.
A television broadcasting wave is converted to an electric signal
by the input means 6001 such as a receiving antenna and then
supplied to the reception means 6004. The reception means 6004
extracts only signals within a necessary band from those supplied
by the input means 6001 and supplies them to the demodulation means
6005. The demodulation means demodulates the signals supplied by
the reception means 6004 to provide digital signals for output and
supplies the demodulation conditions to the delayed wave estimation
means 6007.
Now, the operation of the demodulation means 6005 will be described
below. More specifically, the operation of the demodulation means
6005 consisting of a frequency analysis means 6051, an adjustment
means 6052, and a decoding means 6053 will be described. A signal
supplied by the reception means 6004 is frequency-analyzed by the
frequency analysis means 6051 which performs an FFT, real FFT, DFT,
or FHT frequency analysis technique to convert it to a signal on
the frequency axis and such a converted signal is supplied to the
adjustment means 6052. The adjustment means 6052 operates on the
signal on the frequency axis from the frequency analysis means 6051
based on a control signal supplied by the demodulation adjustment
means [sic] 6055. That operation may be accomplished by performing
a transfer function on a signal supplied by the frequency analysis
means 6051 based on the signal from the demodulation control means
6055, by performing an arithmetic operation through filtering, by
emphasizing a specific frequency component, or by interpolating a
possibly missing frequency component. The signal supplied by the
adjustment means 6052 is decoded by the decoding means 6053 into a
digital code. The delayed wave estimation means 6007 estimates a
delayed wave based on a signal from the demodulation means 6005.
Such reference signals include a frequency spectrum supplied by the
frequency analysis means 6051 and a pilot signal obtained during
the decoding process in the decoding means 6053. The frequency
spectrum of a received signal has dips or the like in response to
the presence of delayed waves as shown in FIG. 147. Since the
frequency spectrum becomes flat in the ODFM modulation which is
usually used for digital television broadcasting, the magnitude of
a delayed wave and the delay time can be estimated. The magnitude
of a delayed wave and the delay time also can be estimated from any
change in phase or missing of a pilot signal. The demodulation
control means 6055 controls the adjustment means 6052 based on
delayed wave information supplied by the delayed wave estimation
means 6007 or the positional information determination means 6008.
Such a control can be accomplished by supplying a control parameter
determined in accordance with the adjustment means 6052 and for
example, by supplying a transfer function determined by the
demodulation control means 6055 in accordance with a delayed wave
when the transfer function is to be applied to the adjustment means
6052. Alternatively, a filter factor is supplied when filtering is
to be performed or an interpolation value is supplied when
interpolation is to be performed. The positional information
determination means 6008 and the vehicle information detection
means 6009 are identical to those for the embodiments 10 and 11
described above and will not be described here in detail.
As described above, according to the present embodiment, accurate
decoding can be accomplished with an improved error rate of
received digital signals, since the adjustment means 6052 serves to
reduce any influence of delayed waves.
FIG. 146 shows the configuration having a plurality of input means
6001. This configuration requires the same number of reception
means as that of the input means as well as a plurality of
frequency analysis means. However, it does not necessarily require
a plurality of adjustment means nor a plurality of decoding means
and it may do with a single adjustment means and a single decoding
means by selecting signals to be processed thereby. It should be
noted that for simplicity, only a single frequency analysis means
6051, a single adjustment means 6052, and a single decoding means
6053 are shown in FIG. 146 but the present embodiment actually
comprises the same number of these means as that of the input means
as described above.
In the configuration of FIG. 146, the magnitude of a delayed wave
and the delay time can be estimated for each input means because a
frequency analysis operation is performed for each input means.
Therefore, the adjustment means 6052 can select a signal of the
best reception conditions. In addition, an appropriate adjustment
can be performed on each signal through such a transfer function,
filtering, or interpolation technique as described above to decode
such a signal in the decoding means 6053. The decoding means
53[sic] or the adjustment means 6052 can select only signals having
a frequency spectrum of good reception conditions among the
frequency-analyzed signals from these input means and thus,
satisfactory decoding of digital codes can be accomplished. From
the foregoing, the configuration of FIG. 146 can correct reception
errors by providing a plurality of input means.
It should be noted that in the different digital television
broadcasting receiving devices according to the present invention,
the maximum gain can be achieved with respect to a wave having a
different plane of polarization by designing each antenna element
to have a different angle when an antenna consists of a plurality
of antenna elements.
INDUSTRIAL APPLICABILITY
As apparent from the foregoing, the present invention provides an
antenna device and a communication system with such an antenna
which can improve the reception sensitivity with a reduced
transmission loss and which can be implemented at a lower cost.
Also, the present invention provides an antenna device which has
better gain characteristics.
In a digital television broadcasting receiving device according to
the present invention (such as claim 38) disturbance due to delayed
waves contained in input signals can be reduced with an improved
error rate after demodulation by delaying input signals immediately
after the input or after the reception and then synthesizing
them.
Also, a digital television broadcasting receiving device according
to the present invention (such as claim 39), disturbance due to
delayed waves can be eliminated properly with an improved error
rate after demodulation by estimating the delay time and magnitude
of delay from a demodulated signal or a signal being demodulated to
control such delay and synthesis operations and then controlling
the delay and synthesis operations based on the estimated delay
time and magnitude of delay.
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